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User Guide: Solid

1. User Guide Solid State NMR Varian NMR Spectrometer Systems With VNMR 6 1C Software Pub No 01 999162 00 Rev A0800 ave TAN VA AJ IAN User Guide Solid State NUR Varian NMR Spectrometer Systems With VNMR 6 1C Software Pub No 01 999162 00 Rev A0800 Revision history A0800 Initial release for VNMR 6 1C software Applicability of manual Varian NMR spectrometer systems with Varian solids modules running VNMR 6 1C software Technical contributors Dave Rice Laima Baltusis Frits Vosman Dan Iverson Evan Williams Technical writers Michael Carlisle Technical editor Dan Steele Copyright 2000 by Varian Inc 3120 Hansen Way Palo Alto California 94304 http www varianinc com All rights reserved Printed in the United States The information in this document has been carefully checked and is believed to be entirely reliable However no responsibility is assumed for inaccuracies Statements in this document are not intended to create any warranty expressed or implied Specifications and performance characteristics of the software described in this manual may be changed at any time without notice Varian reserves the right to make changes in any products herein to improve reliability function or design Varian does not assume any liability arising out of the application or use of any product or circuit described herein neither does it convey any license under its patent rights nor the rights of o
2. 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 104 Chapter 6 Solid State NMR Experiments prep acq pw d1 I _ np 2 times tau 2 tau Figure 49 BR24 Pulse Sequence The macro cy1br24 converts the BR24 parameter set to that suitable to run Cycled BR24 No parameter changes are necessary the preparation pulse are based on the value of pw as described in Table 9 Parameters pw is the 90 pulse length in microseconds p1 is the preparation pulse in microseconds whose phase is controlled by the parameter phasel To minimize the pedestal p1 should be set to the 90 pulse length and phase should be set to 135 degrees by using the parameter phasel tau is the interpulse delay in microseconds that includes pw The BR24 cycle is 36 tau long and is repeated np 2 times to build up the FID np is the number of points acquired trig is setto y or n depending on the system On N TYINOVA and UNITYplus the pulse sequence in not tied to any internal triggering mechanism and t rig should always be set to n On UNITY and VXR data acquisition is triggered to an internal 500 kHz clock so trig must be set to y and the signal of the 500 kHz clock plugged into the external trigger input located on the Pulse Sequence Controller board tauc is the cycle time recalculated each time t au is changed Alterin
3. 89 REDOR 1 Rotational Echo Double Resonance 0 0 0 eee ee ceseeeeceseeeeceeeeeeeeeeeees 91 DOUBLECP 1 Double Cross Polarization 0 0 00 cecescscesecesceseeeeeeseeeeseeeeeeeeaeeees 93 T1ICP1 T Measurement with Cross Polarization cccceccssesesessesecsetecsetecseeceens 95 HAHNCP1 Spin 1 2 Echo Sequence with CP oe ee eeeeeeseeeeeeseeeeceseeeeeeseeees 95 SSECHO1 Solid State Echo Sequence for Wideline Solids A 97 WLEXCH1 Wideline Solids Exchange AA 99 CRAMPS Combined Rotation and Multiple Pulse Spectroscopy ee 100 FLIPFLIP 90 Degree Pulse Calibration 2 0 0 0 eeeecesceesceeeeeeecseeeseceesaeeneeeaes 103 FLIPFLOP Phase Transient Removal 0 cceseseeseeesceeeeeseeeeeeeecaeeeseceesaeesaeeaes 103 HS90 90 Degree Phase Shift Accuracy o0 eee cee eeceeeeeeceeeeeeeeseeeeecaeesaeenaeeaes 104 MREV8 Cycled MREV8 Multiple Pulse Line Narrowing eee 106 BR24 Cycled BR24 Multiple Pulse Line Narrowing 000 0 eee eeeeeeeeeeseeneeees 107 CORY 24 Cycled CORY24 Multiple Pulse Line Narrowing cece 108 MREVCS Multiple Pulse Chemical Shift Selective Spin Diffusion 109 MO SOLIDS Multiple Quantum Solids ee ee eeecesecsseceeeeceeeeeeeeeeeeeteeeeneens 110 SPINDIFF Spin Diffusion in Solids wo eecesessesecseeseeseesecseceeeeceaecaseeceeaeeetees 111 FASTACQ Miultinuclear Fast Acquisition 0 0 0 eee eeceeeeeceeeeeeeeeeeeeeeaeeseeeneeaaes 112 NUTATE Solids 2
4. tpwrm S Du pw pw pw cntct dipolr crossp d1 mix Dec dtau cycles times tau dtau Nl A c Figure 34 CPCS Pulse Sequence Macro The cpcs macro sets up parameters for the CPCS pulse sequence Parameters pw is the IH 90 pulse for cross polarization in microseconds p2 is the contact time in microseconds d2 is the evolution time in seconds dm is set to nny for no proton decoupling during the mixing time dm is set to nyy for proton decoupling during the mixing time Level controls decoupler power during cross polarization level1f controls fine decoupler power during cross polarization level2 controls decoupler power during acquisition 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 80 Chapter 6 Solid State NMR Experiments level2f controls fine decoupler power during acquisition time tau is the time in microseconds between the start of pulses in the multiple pulse sequence In the case of MREV8 the cycle length is 12 tau long mix is the mixing time for spin diffusion in seconds cycles is the number of times through the multiple pulse sequence Reference Spiess H W Schmidt Rohr K Clauss J Blumich B Magn Reson Chem 1990 28 S3 6 15 CPCOSYPS Cross Polarization Phase Sensitive COSY 81 The CPCOSYPS sequence is similar to t
5. Applicability MASEXCH1 is available on Y YINOVA and UNITYplus and present in user1lib It requires a rotor synchronization accessory Rotor speed control is also recommended On request a related sequence C13EXCH is available for older systems Macro The macro masexch1 converts a parameter set obtained with XPOLAR or XPOLAR 1 for the MASEXCH1 experiment Power levels and pulse widths are retained The default is phase 1 2 3 4 and the data are transformed with wft2d 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 Parameters MASEXCH 1 makes use of the YN YINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pwand cntct See page 63 fora description of these parameters pwx is the observe 90 pulse in microseconds phase is 1 2 for P type the Veeman experiment for transformation with wft2d 1 0 0 1 0 1 1 0 and1 2 3 4 for the phase sensitive spectrum according to the reference for transformation with wft2d 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 The phase sensitive spectrum is the sum of a Veeman experiment phase 1 2 and a time reversed experiment phase 3 4 mix is the mixing time in seconds For phase 1 2 3 4 the minimum mixing time is equal to ni 1 sw1 For phase 1 2 the minimum mixing time is 0 0 sync y torun with rotor synchronization sync n to run unsynchronized normal NOESY nt is aminimum of 16 Reference Luz Z Spiess H W Titman J J Israel J of Chem 1992 32 145 6
6. 16 to 63 dB standard 0 to 63 dB is standard on UNITY and VXR S systems Maximum power output is obtained with t pwr 63 To get low power from the high power amplifier tpwr should be decreased by approximately 6 Note that the output of the Observe Transmitter board can be routed to a low power 300 W amplifier LOW POWER position on the third cabinet see Figure 12 or to a high power 1 kW amplifier HI POWER position 3 2 Wideline Experiments Wideline NMR experiments can be divided into three main areas based on spin quantum number I The experiments possible are certainly not restricted to just one of these categories but are normally used in one group rather than in all Table 5 lists commands and parameters related to wideline experiments Table 5 Wideline Experiment Commands and Parameters Commands ssecho Set up solid state echo pulse sequence tmove Left shift FID to time domain cursor tshift Adjust tau2 to current cursor position Parameters dotflag y n Display FID as connected dots lsfid number n Number of complex points to left shift np scalesw number gt 0 0 n Scale spectral width in directly detected dimension Dipolar Nuclei I 1 2 The most common dipolar nucleus is H Many of the dipolar nuclei are not usefully observed under wideline conditions without H decoupling Although the standard wideline probe does not allow double resonance experiments a CP MAS probe can be used
7. 67 81 light pipe for rotor synchronization 52 line broadening in polycrystalline compounds 14 line shape measurement 95 linear attenuator control 16 linewidth reduction 98 liquid samples in a rotor 19 liquids probes for solid state studies 35 LO POWER HIPOWER toggle switch 38 lpower parameter 40 Isfid parameter 39 01 999162 00 A0800 Index M maclib directory 59 magic angle adjustments 22 26 spinning 14 magic echo sequence 108 magic parameter 98 magnet quench warning 9 magnetic media caution 10 magnetization optimum in CP MAS solids 28 magnetogyric ratios 15 making a plug for the standard hollow rotor 19 malonic acid dy sample 41 marking sectors on the rotor 53 MAS experiment 98 masexch macro 69 MASEXCHI1 pulse sequence 68 membrane proteins 84 structures 89 metal objects warning 8 mix parameter 67 81 83 85 98 108 109 mixflag parameter 71 mixing period 97 mloop parameter 109 modifying the instrument 9 modulated CP 72 modulation of the X channel 72 molecular order 97 reorientation 68 monitor spinning stability 25 motor control box 44 mp_at parameter 104 105 mq_solids macro 108 MQ_SOLIDS pulse sequence 108 MREV proton decoupling 86 MREVS8 cycles 86 mrevs macro 48 103 MREVS8 pulse sequence 48 98 103 mrevcs macro 107 MREVCS pulse sequence 107 multinuclear fast acquisition 110 multiple pulse experiments 59 selection 80 sequences 98 mul
8. CP MAS hardware consists of a class A B AMT 3900A 15 linear amplifier that replaces the standard liquids linear amplifier The CP MAS linear amplifier produces output power of up to 100 W in the high band WEI 19F for up to 250 ms The low band remains the same as for the original standard liquids amplifier The fine power control over a range of 0 to 60 dB in 4095 steps is provided by the Transmitter board which is standard on YN TYZNOVA and UNITYplus systems The parameters controlling this are dowrm dpwrm2 and dpwrm3 The attenuator control is linear meaning the control is finer in the higher region than in the lower region of the attenuator as shown in Figure 1 In addition a pneumatics tachometer box is used for controlling air flow and spinning speeds CP MAS Hardware for UNITY and VXR S Systems The CP MAS solids module is the only one of the solids hardware configurations that does not require the solids cabinet Apart from the special probe the hardware for the standard performance CP MAS solids module consists of a 100 W narrow band decoupler pulse 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 16 Chapter 2 CP MAS Solids Operation 17 60 dB 54 dB 48dB gt 42 dB 36 dB 0 255 511 1023 2047 4095 Figure 1 Linear Attenuator Control Graph amplifier a fine attenuator a power control box on 200 MHz and 300 MHz systems and a pneumatics tachometer box The ampli
9. For closely spaced resonances p1 may need to be longer to achieve greater selectivity It should be noted that for strong coupling significant mixing occurs during the inversion pulse and so a shorter less selective inversion pulse may be preferred tpwrms is the observe linear modulator setting for the selective pulse The default is tpwrm 50 To obtain tpwrms for a given inversion pulse length p1 set tof2 see tof2 below set mix to 0 0 and array the value of tpwrm about the default value Choose the value corresponding to the maximum negative signal for the resonance of interest tof2 is the transmitter offset of the resonance to be selectively inverted To obtain tof2 use xpolar1 to acquire a spectrum in a second experiment place the cursor on the resonance of interest and enter movetof Set tof2 in r2selpuls1 equal to the this tof mix is the mixing period in milliseconds Use caution because setting dm y during the mix period may lead to an unacceptable duty cycle srate is the actual spinning speed Rotational resonance requires spinning speed control Set the spinning rate equal to the frequency difference between the two resonances of interest first sideband or to an integral nth division nth sideband References Raleigh D P Levitt M H Griffin R G Chem Phys Lett 1988 146 71 Raleigh D P Cruezet E Das Gupta J K Levitt MH Griffin R G J Am Chem Soc 1989 111 4502 6 18 DIPSHFT1 Se
10. R A J Magn Reson 1984 57 471 6 22 T1CP1 7 Measurement with Cross Polarization The pulse sequence T1CP1 is used to measure the T of X nuclei e g 130 by cross polarization CP as published by Torchia Figure 42 is a diagram of the sequence 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NMR 92 Chapter 6 Solid State NMR Experiments 6 23 93 cntct pwx pwx tpwrm d2 at Tx A pw cntct dipolr crossp Dec di Figure 42 T1CP1 Pulse Sequence Macro The macro t 1cp converts a parameter set obtained by XPOLAR or XPOLARI for the measurement of T4 Observe and decoupler power levels and the 90 pulse width are retained By default pwx pw Fine calibration of pwx is recommended Parameters T1CP1 uses the YN TYZNOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dplv12 pw and cntct See page 63 for a description of these parameters pwx is the observe 90 pulse in microseconds d2 is the delay of the 7 inversion recovery in seconds Reference Torchia D A J Magn Reson 1978 30 613 HAHNCP1 Spin 1 2 Echo Sequence with CP The HAHNCP 1 pulse sequence provides a 90 tau 180 tau Hahn spin echo If xpol y the initial 90 pulse is replaced by cross polarization If xpol n the spin echo sequence is done Use HAHNCP1 to obtain static lineshape for spin 1 2 powder spectra to avoid pulse ring down and first
11. This board also contains a Bessel filter either 256 kHz 6 pole Bessel or 1 MHz 4 pole Bessel This filter is switched in when sw is less than 256 000 Hz otherwise the 1 MHz filter on the receiver is used 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 34 Chapter 3 Wideline Solids Module Operation 35 e The older Wideline ADC board was shipped with UNITY and VXR S systems It acquires data in a fundamentally different manner Data is temporarily stored in its on board 2 x 8 Kword buffer maximum np is 16384 After each FID is collected data is transferred to the normal acquisition memory and the fast memory is cleared This process requires an overhead of about 32 us for each complex point Both ADC boards are single VERSAbus boards containing sample and hold modules ADC chips memory and control logic and each board is capable of digitizing 12 bits in 500 ns The ADC conversion time is adjustable in 25 ns steps so there are only a limited number of actual values that the spectral width can take The entered value of sw is automatically adjusted to the nearest valid spectral width The standard Observe Receiver board for N YINOVA and UNITYplus systems has the correct bandwidth amplifier and is not replaced For UNITY and VXR S systems the Wideline Receiver and Filter board is a replacement of the standard 100 kHz receiver and contains filters appropriate for both small and large spectral widths Improved filters give
12. better baseline and phase characteristics however they may show a 10 reduction in signal to noise as determined by the standard 13C test For spectral widths above 100 kHz 6 pole true Table 4 Bessel Filter Outputs Bessel filters are used The outputs from these filters are routed to the wideband ADCs The permissible values of the parameter fb which are SW KHR epee identical to the 3 dB points of these filters are 100 225 256 listed in Table 4 gt 225 1000 For 100 kHz and below the signal is routed 300 540 300 through a pair of 8 pole quasi elliptical filters to 540 1260 700 standard ADCs The characteristics of these filters 1260 1800 1000 provide superior performance for both phase and gt 1800 2400 amplitude flatness across the full spectral width The Wideline NMR Module for the YNTYZNOVA system is a board that includes two 5 MHz 12 bit ADCs and 2 MB of onboard memory High Power Amplifier The wideline high power 1 kW amplifier is intended mainly for use in solid state NMR studies The amplifier is housed in a third cabinet as shown in Figure 12 and configured to permit maximum flexibility Manual controls permit selection of either the solids amplifier or the standard liquids amplifier for the observe function CAUTION Never use probes designed for liquids studies with amplifiers intended for solid state studies The high power from these amplifiers will destroy liquids probes Because
13. controlled by parameters alfa beta and fb is not present in ssechol Adjust tau2 or use 1sfid to set the beginning point of the Fourier transform 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 96 Chapter 6 Solid State NMR Experiments References Mansfield P Phys Rev 1965 137 A961 Weisman I D Bennett L H Phys Rev 1969 181 1344 6 25 WLEXCH1 Wideline Solids Exchange Two dimensional NMR offers a unique method of characterizing molecular order and molecular dynamics in solid materials such as polymers This technique can be used to study ultra slow on the NMR time scale dynamic processes occurring on a time scale of 1 millisecond to 100 seconds In an axially symmetric SS powder pattern Pake doublet the exchange signal patterns supply immediate information about the type and rate of the dynamic process Two dimensional 7H exchange spectroscopy can be used to determine the angle at which a selectively deuterated group rotates during a defined mixing period Lei Isolated cross peaks are observed in 2D exchange spectra of liquids and crystals The exchange signals in the 2D exchange spectra of solid powders are actually very broad spectra The molecular reorientation of the deuterated group in the molecule occurs at a particular angle relative to the molecular axis At a given mixing time one ellipse for each of these reorientation angles can be measured Applicability WLEXCH1 is available only onY
14. multiple of the rotor speed At the r condition each resonance is split into a characteristic doublet pattern that can be simulated to obtain the coupling constant and internuclear distance If one of the resonances is selectively inverted the two will equilibrate to a common signal intensity The recovery curve can also be simulated to obtain the coupling constant Rotational resonance is often used for the determination of the structure of biomolecular materials such as membrane proteins CPNOESY with rfdr y provides similar information Applicability R2SELPULS1 found in user1ib is available only on UN TYINOVA and UNITYplus 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 84 Chapter 6 Solid State NMR Experiments Macro The macro r2selpuls1 converts a parameter set obtained with XPOLAR or XPOLAR1 for rotational resonance with selective inversion RASELPULS1 Power levels and the proton 90 pulse width are retained The length of the inversion pulse is estimated to be 50 pwx and the power is set accordingly Fine calibration of the inversion pulse is required Parameters r2selpulsi1 uses YINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters The selective inversion pulse must be calibrated pwx is the observe 90 pulse in microseconds p1 is the observe selective inversion pulse in microseconds The default is 50 pwx
15. tau parameter 81 86 101 102 103 105 107 108 109 taul parameter 94 96 98 tau2 parameter 94 96 98 tauc parameter 104 105 107 third cabinet 36 third channel settings 90 92 through space dipolar interaction 84 VNMR 6 1C User Guide Solid State NMR 116 Index timed spin echoes 65 TMS referencing 31 tof parameter 110 tof2 parameter 85 Torlon end caps 18 56 toss parameter 28 60 62 65 TOSS pulse sequence 28 60 total sideband suppression 60 Total Sideband Suppression technique 28 toxic samples 19 tpwr parameter 37 38 40 45 64 96 111 tpwrf parameter 26 45 tpwrm parameter 40 64 96 97 tpwrm2 parameter 85 tram tracks FID 47 Transmitter board 16 trig parameter 46 101 102 104 105 107 trigger point 50 triggering mechanism 101 103 104 105 107 triple quantum MAS experiment 77 triple resonance experiments 59 91 triple resonance probe 89 110 troubleshooting solids sample spinning 22 U unnarrowed spectra of solid samples 34 upper barrel warning 9 user library 59 userlib directory 59 V vacp macro 75 vacp parameter 75 VACP pulse sequence 75 vacplist macro 75 variable temperature VT experiment warning 9 operation with solids 56 57 operation with solids rotors 18 pneumatics tachometer box 54 Varian rotors 18 20 53 Varian Solids Variable Temperature Accessory 56 VERSAbus board 35 Vespel end caps 18 57 VNMR manuals Command and Parameter R
16. which has a menu driven interface The main menu provides choices that initiate the following e Open loop e Closed loop e Configuration routines e Exit from the rcontrol software Open Loop Mode In open loop O mode the program requests a DAC value 0 to 65385 and then continually displays the rotor speed on the screen Open loop mode is useful when spinning a sample up for the first time perhaps to check packing balance or to calibrate the electro pneumatic regulator span and zero settings 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 54 Chapter 5 Solid State NMR Accessories The DAC value can be changed while continuously displaying the rotor speed by pressing the following keys and simultaneous key combinations on the PC keyboard Actions Keys Decrease DAC value by 1 unit f Decrease DAC value by 100 units l Decrease DAC value by 1000 units Shift l Increase DAC value by 1 unit Shift f Increase DAC value by 100 units h Increase DAC value by 1000 units Shift h Exit to main menu q Closed Loop Mode In closed loop C mode the desired rotor speed is entered The control algorithm then takes over to control the rotor speed While controlling is active the DAC value latest increment to the DAC and the difference of the rotor speed and the set point are displayed each time through the control loop To stop the speed control process press the q key After the process is stopped you can enter a new
17. 0 see p180 and pdp d2 is in seconds e srate is the sample spinning speed in Hz e toss set to y implements timed spin echoes to suppress spinning side bands Timing is determined from the value of srate Note that for toss y or pdp y srate must be set because delays of 1 0 srate are used 6 3 XPWXCAL Observe Pulse Calibration with 65 Cross Polarization The pulse sequence XPWXCAL derived from XPOLARI is used to calibrate the observe 90 pulse if observe pulses are to be used explicitly in pulse sequences Because cross polarization is used for preparation XPWXCAL can be run in less time than XPOLARI with xpol n Figure 26 is a diagram of the sequence Applicability XPWXCAL is available only on YN TYZNOVA and UNITYplus It is found in userlib VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 3 XPWXCAL Observe Pulse Calibration with Cross Polarization lt if phase 2 gt cntct pwx tpwrm X Y h at Tx i d2 pw cntct dipolr crossp d1 Dec ee eg A Cc Figure 26 XPWXCAL Pulse Sequence Macro The macro xpwxcal converts a parameter set obtained with XPOLAR or XPOLARI for the XPWXCAL experiment Power levels and the proton 90 pulse width are retained By default pwx pw and phase 2 Parameters xpwxcal uses the Y YINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description o
18. 00 A0800 VNMR 6 1C User Guide Solid State NUR 22 Chapter 2 CP MAS Solids Operation 23 Figure 2 Typical MAS Spectrum of Adamantane adjusted the magic angle should stay fairly constant However this is not guaranteed The angle should be checked and adjusted as follows e When the probe is inserted in the magnet e Every day or second day of continuing operation e If linewidths in any particular sample are suspiciously large Once typical values for the minimum linewidths are established for any particular instrument these values can be taken as a reliable indication of proper angle Adjustment of the angle is neither necessary nor desirable if the first measurement indicates that the minimum linewidth has been achieved Coarse Adjustment 7 54 7 A convenient method of setting the Se sample angle to the approximate magic angle before final optimization with NMR is to use the angle measuring stem Part No 00 992825 00 and angle be Angle measuring stem measuring gauge Part No 00 992826 SCH 00 from the rotor and tool kit Figure 3 Angle measuring gauge illustrates how the angle measuring stem and angle gauge are used ___ Probe I Fine Adjustment i Figure 3 Tools for Coarse Adjustment of The preferred method of adjusting the Sample Angle magic angle uses the 79Br spectrum of KBr which has a large chemical shift anisotropy CSA When spun at the magic angle this results in an extensive se
19. 180 pulse tau2 is the delay in microseconds between the 180 pulse and the acquisition The additional delay for filter response alphat fn beta is also present Reference Hahn E L Phys Rev 1950 80 580 Carr H Y Purcell E M Phys Rev 1954 94 630 Rance M Byrd R A J Magn Reson 1983 52 221 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 94 Chapter 6 Solid State NMR Experiments 6 24 SSECHO1 Solid State Echo Sequence for Wideline 95 Solids Non narrowed spectra of solids samples can often reveal a considerable information In wideline NMR no attempt is made to narrow the resonances and patterns of 100 kHz or wider can occur For wideline NMR the line shape is of the utmost importance and the spectrometer must be able to measure very broad lines without distortion For this reason the transmitter power must be high and the value of YB must be large enough to uniformly excite the entire spectrum The effects of a finite 90 pulse can be investigated with simulations using the solids analysis software accessory With linewidths in excess of 100 kHz an increase in ADC analog to digital converter speed 2 MHz or 5 MHz is necessary Often the typical spectral widths used far exceed the linewidths Oversampling and digital filtering are used to reduce the data size For quadrupolar nuclei the main cause of linewidth is the quadrupolar coupling of the nuclei being observed The observ
20. 35 36 aromatic carbons magic angle adjustment 22 attenuation computer controlled 38 automatic teller machine ATM cards caution 10 B B pulses 98 bearing pressure and flowrate 21 Bessel filter 34 35 biomolecular materials structure definition 84 structures determination 89 blackened sector on rotor base 52 blew parameter 70 BLEW 12 cycles 70 bmult parameter 70 body nitrogen for solids probe VT operation 56 booster power supply for VT controller 56 br24 macro 104 BR24 pulse sequence 98 99 104 Br81 24 C C13EXCH pulse sequence 69 calibrating decoupler power for CP MAS solids 26 pulse width in CP MAS solids 26 pulse width in wideline experiments 40 calibration experiments 100 carbon chemical shifts 31 carbonyls magic angle adjustment 22 01 999162 00 A0800 Index cautions defined 8 cavity end plates 44 change bar 12 change samples 40 chemical shift anisotropy CSA 14 22 23 98 differences 80 tensor components 77 chemical shift Hamiltonian 99 clock signal 101 102 103 105 closed loop C mode 55 CMOS BIOS setup 56 cntct parameter 64 cntct2 parameter 92 coarse materials in a rotor 19 Combined Rotation amp Multiple Pulse Spectroscopy 98 Complete Solids module 15 composite echo 96 compul parameter 96 computer controlled attenuators 17 contact time 60 array 27 macro 60 continuous mode amplifier operation 36 conventions used in manual 12 cory24 macro 106
21. CORY 24 pulse sequence 99 105 COSY pulse sequence 81 CP MAS experiments 59 hardware 16 cp90 parameter 67 cpcosyps macro 81 CPCOSYPS pulse sequence 81 cpces macro 80 CPCS pulse sequence 80 CPNOESY experiment 84 cpnoesyps macro 82 CPNOESYPS pulse sequence 82 cppwr parameter 63 65 CRAMPS Multipulse module operation 44 49 experiment 98 probe 45 credit cards caution 10 crossp parameter 65 73 crossp2 parameter 92 cross peaks 68 cross polarization contact time 64 NOESY 82 samples 60 spectra 28 time 27 cycled BR24 pulse sequence 105 CORY 724 pulse sequence 105 MREVS8 pulse sequence 103 cycles parameter 81 88 90 108 cylbr24 macro 105 cylcory24 macro 106 cylmrev macro 103 VNMR 6 1C User Guide Solid State NUR 112 Index D d1 parameter 28 d2 parameter 29 62 65 67 80 93 96 DAC value 55 damaged rotors 21 dark to light edge on rotor 50 data processing of wideline experiments 43 dbcpflag parameter 92 dblvl2 parameter 63 65 dec2flag parameter 91 decay time constant 61 decoupler amplifier 17 37 44 linear modulator 64 patterns 71 power setting 63 64 del parameter 108 delp parameter 108 dephasing time 61 depolarization 76 DEPT experiment 60 detection mark on rotor 50 deuterium powder pattern spectrum 41 wideline experiments 39 dfrq2 parameter 90 dhp parameter 17 dilute spin Hartman Hahn match 92 dipof2 parameter 70 dipolar coupling 14 couplin
22. Polarization UTYINOVA amp UNITYplus cceccccccceceteeeeeeteeneeees 65 XPWXCAL Observe Pulse Calibration with Cross Polarization 0 0 0 0 sees 67 XNOESYS YNC Rotor Sync Solids Sequence for Exchange s s s 69 MASEXCH1 Phase Sensitive Rotor Sync Sequence for Exchange s es 70 HETCORCP 1 Solid State HETCOR 00 ceceseceeceseeeeceseeeeseeeeeeseseeeeesaeseeeenees 71 WISE1 Two Dimensional Proton Wideline Separation 2 0 0 0 eceeceeeseeeeeeeeeeees 72 XPOLWFG1 Cross Polarization with Programmed Decoupling eee 73 XPOLXMOD 1 Waveform Modulated Cross Polarization sees eeeeseeeeeeees 74 VACP Variable Amplitude Cross Polarization cceseeeesceeeceeeeeeseeeeeeeeneeseees 76 XPOLEDIT1 Solids Spectral Editing oe ee eeseseecseeseeceeceeecaeseaeeeesseeeeees 78 3QMAS1 Triple Quantum 2D for Quadrupole Nuclei ccceeceeseeeceeeeeeeeeeees 719 PASS 1 2D Sideband Separation for CP MAS uo cceeeseeeceeceeeneeeeceecaeeeeeaetaeenees 80 CPCS Cross Polarization with Proton Chemical Shift Selection 0 0 ee 82 CPCOSYPS Cross Polarization Phase Sensitive COSY ooo ee eee eeeeeereeeeeeee 83 CPNOES YPS Cross Polarization Phase Sensitive NOESY n se 84 R2SELPULS 1 Rotation Resonance with Selective Inversion eeeeeeeeeeee 86 DIPSHFT 1 Separated Local Field Spectroscopy eseeseesceeceeeeeeeeeeeeeeeeeaeeees 88 SEDRA2 Simple Excitation of Dephasing Rotational Echo Amplitudes
23. accessory manuals are also provided online so that you can view the pages on your workstation and print copies Types of Varian NMR Spectrometer Systems In parts of this manual the type of spectrometer system UN TYINOVA MERCURY VX MERCURY GEMINI 2000 UNITY plus UNITY or VXR S must be considered in order to use the software properly e UNITYTNOVA and MERCURY VX are the current systems sold by Varian e UNITYplus UNITY and VXR S are spectrometer lines that preceded the UN YINOVA e MERCURY and GEMINI 2000 are spectrometer lines that preceded the MERCURY VX Help Us to Meet Your Needs We want to provide the equipment publications and help that you want and need To do this your feedback is most important If you have ideas for improvements or discover a problem in the software or manuals we encourage you to contact us You can reach us at the nearest Varian Applications Laboratory or at the following address Palo Alto Applications Laboratory Varian Inc NMR Systems 3120 Hansen Way MS D 298 Palo Alto California 94304 USA VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Chapter 1 Overview of Solid State NMR Sections in this chapter e 1 1 Line Broadening this page e 1 2 Spin Lattice Relaxation Time page 15 e 1 3 Solids Modules Probes and Accessories page 15 Before techniques were developed to obtain high resolution NMR spectra of compounds in the solid state the spectra of these s
24. amplifiers will destroy liquids probes Use the appropriate high power probe with the high power amplifier Take electrostatic discharge ESD precautions to avoid damage to sensitive electronic components Wear grounded antistatic wristband or equivalent before touching any parts inside the doors and covers of the spectrometer system Also take ESD precautions when working near the exposed cable connectors on the back of the console Radio Frequency Emission Regulations 11 The covers on the instrument form a barrier to radio frequency rf energy Removing any of the covers or modifying the instrument may lead to increased susceptibility to rf interference within the instrument and may increase the rf energy transmitted by the instrument in violation of regulations covering rf emissions It is the operator s responsibility to maintain the instrument in a condition that does not violate rf emission requirements VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Introduction This manual is designed to help you perform solid state NMR experiments using a Varian solid state NMR module on a Varian NMR spectrometer system running VNMR version 6 1C software The manual contains the following chapters Chapter 1 Overview of Solid State NMR provides an short overview of solid state NMR including the types of solids modules probes and accessories available Chapter 2 CP MAS Solids Operation covers using the CP
25. and spun below its vibration speed for a few minutes If the sample seems intact on the surface then it is more than likely not homogeneous or did not pack evenly VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 4 Adjusting Homogeneity In the case of a machined plug the material can have a void or it can fit too loosely in the rotor cavity The only solution is to remove all the sample and repack the rotor With inhomogeneous materials this repacking may have to be tried more than once CAUTION When removing caps or digging out packed samples take care not to gouge the rotor Even small scratches can imbalance the rotor At times worn rotor caps cause imbalance Changing caps or rotating them between rotors sometimes cures these problems Probe Adjustments for Improved Spinning Increased bearing pressure often stabilizes samples that do not spin well This adjustment must be made at low speed and then ramped up once the rotor spinning is stable 2 4 Adjusting Homogeneity Homogeneity should be adjusted as follows on a sample of D20 prepared in a standard rotor and tightly capped using a cap with a concentric drilled hole 1 Insert and seat the sample and install the probe into the magnet spin slowly several hundred Hz or less with 2 0 bar 0 5 bar bearing pressure and a very low drive rotation pressure Generally this slow spinning speed barely registers on the tachometer Note that with time D20 spins out of
26. are also present pattern is a string with the name of the DEC file used for modulation pwpulLs is the amplitude of the linear modulator during only the initial proton pulse of XPOLHMOD1 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 10 VACP Variable Amplitude Cross Polarization crossp is the amplitude of the proton linear modulator during cross polarization and this value scales the waveform for XPOLHMOD1 tpwrm is the amplitude of the X linear modulator during cross polarization and this value scales the waveform for XPOLXMOD1 Waveforms Two macros are provided to calculate commonly used waveforms a cosine function and a ramp For general waveforms to be used for cross polarization a duration of 1 0 in the first column must be 0 2 microseconds dmf and dres are not used to control the cross polarization waveform You can also set programmed decoupling during acquisition by the usual procedure using dmf and dres xmodcos frac per amp creates a waveform with the following function amp 1 0 frac 2 0 frac 2 0 cos t per where t is time The resulting DEC file has the form xmodcos_frac_per_amp DEC where frac is x10000 and per is in microseconds The defaults are per 1 srate the value needed for reference 1 and amp 1023 xmodramp frac per amp creates a waveform with the following function amp 1 0 frac 2 0 frac 2 0 1 0 4 0 t per for 0 0 lt t lt per 2 0 and
27. decoupling spectra 28 gating input to linear amplifier 37 generic power parameters 96 granular materials in a rotor 19 H h2cal macro 27 hahncp1 macro 94 HAHNCPI pulse sequence 93 Hartmann Hahn condition 60 66 matching 27 helium contact with body 9 gas flowmeters caution 11 HETCOR pulse sequence 69 hetcorcp1 macro 70 HETCORCP1 pulse sequence 66 heteronuclear chemical shift correlation 69 dipolar coupling 14 hexamethylbenzene HMB 25 27 HI POWER 01 999162 00 A0800 LO POWER toggle switch 38 ENABLE subpanel 37 high power amplifier cautions 11 for wideline solids 35 high speed probes 21 hollow rotor 19 homogeneity adjustments 22 homogeneous machinable solids 19 homonuclear carbon dipolar interaction 87 correlation experiment 81 hs90 macro 102 HS90 pulse sequence 102 hsrotor parameter 53 I imbalance in sample material 21 in parameter 54 internuclear distance 89 inversion pulse 85 inversion recovery experiment 62 solid echo experiments 39 irregular granular materials in a rotor 19 isotropic spectra of quadrupole nuclei 77 spectrum 2D plot 78 J J coupling 60 experiments in solids 29 jitter in TTL rotor synchronization period 52 K KBr 1 2 Turn Off Angle 25 KBr On Angle 24 Kel F end cap 18 L Larmor frequency 60 levell parameter 26 27 62 63 67 80 levellf parameter 62 67 80 level2 parameter 18 26 63 67 80 level2f parameter 26 63
28. nucleus The macro s3qmas1 uses pw to calculate the default 180 pulse pw is not used in the pulse sequence pw3q is the length of pulses 1 and 2 of 3QMAS1 It is used to generate triple quantum coherence pulse 1 and then return it to single quantum coherence pulse 2 for detection The default is pw3q 2 pw Set pw3q to a larger value e g pw3q 8 pw for greater triple quantum signal to noise in some cases tpwr is the observe coarse attenuator setting for pulses and 2 tpwrm is the observe linear modulator setting for pulses 1 and 2 tpwrs is the observe coarse attenuator setting for the selective refocusing pulse pulse 3 The default is tpwrs tpwr tpwrms is the observe linear modulator setting for the selective refocusing pulse pulse 3 The default is towrms tpwrm 5 but this pulse must be calibrated pws is the length of the optional selective refocusing pulse pulse 3 The default is pws 0 0 and the refocusing pulse is absent For refocusing set pws 10 pw for the default value of towrms tpwrm 5 srate must be set to the actual rotor speed This value is used with periods to calculate the delay t au before the refocusing pulse periods is the number of rotor periods before the selective refocusing pulse This delay is present only if pws gt 0 0 and by default it is absent das 1p is a processing parameter required to shear the triple quantum 2D dataset and rotate the narrow axis of each correlation to the f1 dime
29. pressure not exceeding 120 psig 8 bar and be filtered to 0 6 micron CAUTION Failure to maintain a clean and dry air supply shortens probe life This section contains general information about the RT and VT Pneumatics Tachometer Boxes and installation instructions Figure 17 shows a Pneumatics Tachometer Box for VT variable temperature CP MAS probes This box is mounted on a leg of the magnet in a convenient position The four hoses coming out of the left side of the pneumatics box are connected to the probe ROTATION DRIVE BEARING BODY GAS and the EJECT port of the magnet These connectors are of a high pressure quick disconnect type 5 2 Rotor Synchronization Operation In anumber of experiments it is desirable to trigger an event at a precise point in the rotation period of a rotor Usually this is less relevant from transient to transient than it is within a single transient Even within a single transient the required delay before the trigger point may be some seconds or minutes This delay is long enough for the rotor to change speed enough so that dead reckoning is not sufficiently accurate The rotor synchronization accessory offers the spectroscopist the ability to synchronize events with the absolute position of a CP MAS rotor as well as to read the rotor speed at any time Hardware Description The rotor synchronization hardware detects the optical transition from dark to light of the detection mark on a rotor and p
30. rotor cycles before detection An array is most often set with cycles 2 4 to the number of maximum cycles typically 64 Be sure the parameter array is inthe order cycles rdflag and not the reverse pwx is the observe 90 pulse length in microseconds obtained with xpwxcal after you have adjusted the Hartmann Hahn match dpwr2 is the third channel coarse attenuator setting 16 dB to 63 dB dpwrm2 is the third channel linear modulator setting 0 to 4095 dn2 is the third channel nucleus dfrq2 is the third channel frequency in MHz dof2 is the third channel decoupler offset in Hz do 2 should be determined by direct observation of the spectrum of the third channel nucleus p1 is the third channel 180 pulse in microseconds The power levels dpwr2 and dpwrm2 determine the required pulse length p1 is set with the REDOR1 experiment Set cycles toa small value such as 4 and rdflag y For given third channel power levels array p1 from 0 to about 30 microseconds Set p1 equal to the value corresponding to first intensity minimum 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 90 Chapter 6 Solid State NMR Experiments srate is the actual spin speed REDORI requires rotor speed control Synchronization of the 7 pulses with the rotor period is obtained by automatic calculation of delays from the value of srate dec2flagissetto n for normal operation dec2 flag interchanges the pulses for the observe and th
31. safety shield and full face shield at all times Never use rotors that have been dropped onto a hard surface since microscopic cracks in the rotor material can cause rotor explosions at much lower spinning speeds than indicated in Table 2 Never spin zirconia white rotors at spinning speeds above 7 2 kHz Never spin silicon nitride gray rotors at speeds above 9 5 kHz Never apply air drive pressure above 72 5 psig 5 0 bar Table 2 Typical Spin Rates with Associated Bearing and Drive Values Bearing Drive Spinning Speed Hz 250 Hz Pressure Flow rate Pressure Flow rate psig bar LPM 2 LPM psig bar LPM 2 LPM 2500 28 2 0 12 5 7 0 5 15 0 4000 28 2 0 12 5 14 1 0 20 0 5000 36 2 5 12 5 21 1 5 25 0 6000 36 2 5 12 5 28 2 0 27 5 6500 36 2 5 12 5 35 2 4 29 5 7200 36 2 5 12 5 36 2 5 30 0 7500 39 2 7 12 5 44 3 0 32 5 8000 44 3 0 10 0 51 3 5 35 0 8500 44 3 0 10 0 58 4 0 37 5 9000 44 3 0 09 0 65 4 5 40 0 To Spin Samples in Doty Probes Either one or two air supplies can be used for sample spinning in the Doty probe Because the control box supplied for CP MAS has two controllers split streams are recommended The techniques for doing this are covered in the Doty probe manual 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NMR 20 Chapter 2 CP MAS Solids Operation 21 To Spin Samples in High Speed Probes Table 2 lists spin rates and the appropriate bearing and drive pres
32. simplify phasing of the transformed FID the echo is Fourier transformed from the top onwards in time The extra data points are ignored using 1sfid To accurately define the echo top these echoes are usually over digitized Quadrupolar Nuclei I gt 3 2 Quadrupolar nuclei are also observed via echo sequences however as different types of lineshape information may be sought a number of different echo sequences may be used depending on the quantum transitions of interest I D Weisman and L H Bennett Phys Rev 181 1344 1969 3 3 SSECHO Pulse Sequence One basic pulse sequence SSECHO is provided to support quadrupolar wideline experiments This pulse sequence can perform conventional solid echo experiments with or without composite pulses It also supports inversion recovery solid echo experiments as well as echo experiments with unequal pulse widths The details of this pulse sequence are discussed in Chapter 6 which also provides a model for users for whom other variations of the experiment may be of interest Since this pulse sequence like all others undergoes periodic revision and improvement you are encouraged to print the version current in your software with the ptext command ptext vnmr psglib ssecho c The SSECHO pulse sequence is not appropriate for proton relaxation studies 3 4 Data Acquisition 39 For data acquisition consider sample preparation shimming and pulse width calibration S
33. suppression experiment on alanine obtained by setting pdp protonated dephasing equal to y setting srate to the spinning speed and entering appropriate values for d2 in seconds the dephasing time VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 10 Optimizing Parameters and Special Experiments xpol y pdp y level2 pw level1 p2 2 pw 13 S d2 1 srate i 1 srate Figure 9 Protonated Carbon Suppression of Alanine Spectrum and Sequence 13C me Experiments Measurements of the spin lattice relaxation time in the rotating frame Tip are possible using the standard XPOLAR pulse sequence Anytime that p3 is set to a non zero value a Tip decay is introduced thus by setting p3 to an array Tip is measured Typical values for p3 would range from 50 to 5000 us To analyze a fie experiment for the decay time constant enter analyze texpfit p3 t2 list or use the menu buttons for T gt analysis In experiments other than Tip experiments p3 should be set to 0 Figure 10 shows the spin lattice relaxation measurement pulse sequence 1H 7 Through SC Cross Polarization H T can be measured using the XPOLAR pulse sequence by setting it up to perform a standard inversion recovery experiment on the protons followed by cross polarization of the remain H magnetization to the carbons Figure 11 illustrates the pulse sequence 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR
34. the rotor 2 Tune the probe to observe 2H by inserting the proper tuning stick and adjusting the probe tuning controls 3 Attach the lock cable to the observe OBS connector on the probe 4 Lock the spectrometer and shim on the lock signal A typical procedure is to first adjust Z1 X Y and Z2 then to adjust XZ YZ XY and X2Y2 Readjust Z1 and Z2 Finally adjust any other off axis shims as necessary 5 To see how well the field homogeneity has been adjusted do the following a Turn the lock transmitter off by entering Llockpower 0 lockgain 0 su Disconnect the lock cable from the probe b Connect the cables so that the observe OBS port of the probe is connected to the observe connector on the magnet leg c Acquire a deuterium spectrum using the deuterium parameter set contained in the library of standard parameter sets The deuterium linewidth should be typically between and 5 Hz Finer adjustment and evaluation of the homogeneity is possible using a sample of solid adamantane not available from Varian A linewidth between 2 and 10 Hz is typically attainable as shown in the sample spectrum in Figure 2 2 5 Adjusting the Magic Angle Improper adjustment of the magic angle results in incomplete collapse of the chemical shift anisotropy CSA pattern For carbons with significant anisotropy such as aromatics and carbonyls this can greatly affect the linewidth of the observed resonance In general once 01 999162
35. the spinning speed dependence of cross 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 74 Chapter 6 Solid State NMR Experiments polarization In the VACP sequence during the contact time IH power is varied among 11 levels with the appropriate amplitudes The difference between the maximum and minimum values of yB in Hz should be at least twice the maximum rotor speed to be used Figure 30 is a diagram of the VACP sequence cntct tpwrm at TX d cnict on dipolr d1 vacp 11 Dec eg A c Figure 30 VACP Pulse Sequence Applicability VACP is available on Y TYINOVA UNITYplus and UNITY It is found in userlib Macro The vacp macro sets up parameters for the VACP pulse sequence and can take two or three arguments vacp sets default levels for the arrayed parameter vacp Units are the same as crossp vacp 0 crossp vacp n vacp n 1 500 and n 11 Syntax is as follows vacp lt lt lt lt vacp n vacp n 1 vacp 0 gt n gt gt The vacplist macro lists VACP levels and resets array two single quotes Parameters VACP uses the YNTYZNOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr dblv12 pw and cntct See page 63 for a description of these parameters vacp is an array of linear modulator settings to be used during cross polarization After vacp is set set array The command da is ino
36. the system and make the necessary adjustments to achieve the required performance The experiments use the response of a test sample usually doped benzene in a microsphere to the determine the state of the instrument FLIPFLIP is described below and FLIPFLOP is covered in the next section On a Varian spectrometer the experiment a FLIPFLIP and FLIPFLOP are run from 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NVR 100 Chapter 6 Solid State NMR Experiments the one sequence FLIPFLOP The pulse sequence is 90 phase1 acq 90 phase2 acq The type of experiment being done is determined by the value of the parameter phasel and phase2 FLIPFLIP is used to determine the exact 90 pulse This experiment requires transmitter to be on resonance for proper results The FLIPFLIP pulses move the magnetization in 90 increments Each pulse in the pulse train is separated by a delay t au during which the receiver is turned on and the evolution of magnetization is detected The value of phasel phase2 0 Macro The macro flipflop recalls the sequence and a modified parameter set Parameters pw is the pulse length in microseconds usually set to a 90 pulse phasel1 is the phase of the first 90 pulse and is set to 0 phase2 is the phase of the second 90 pulse and is set to 0 trigissetto y or n depending on the system On UN YINOVA and UNITYplus the pulse sequence in not tied to any internal triggering mechanism and
37. very long in solids It may be necessary to set d1 to values of the order of 100 seconds in some cases 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 42 Chapter 3 Wideline Solids Module Operation e Remember that for solid samples of quadrupolar nuclei the 90 pulse usually cannot be determined from a pw array 3 6 Data Processing 43 Most data processing needs of wideline spectra are the same as that for other spectra There are however several specialized applications for which software is provided Since most wideline spectra are collected in a spin echo mode it can be extremely important to start acquisition or at least Fourier transformation on top of the echo The FID display program provides a point by point if dot lag y two color display of the real and imaginary channels of the FID in order to provide the best possible examination of the details of the FID One or two time cursors can also be displayed and are not constrained to fall on top of individual data points but may be used to interpolate as well for example to estimate the time of the echo A left shift of the FID may be used to shift the FID until the echo occurs at the first point of the FID Normally the echo top is well enough defined so that left shifting removes all distortion However this is not always the case especially with very short T2 echoes A means of fractionally left shifting has been provided as follows lsfid n phfid
38. 1 2 for hypercomplex phase sensitive detection Use the command wft2d 1 0 0 0 0 0 0 N for transformation usually 0 5 lt N lt 2 0 Spin lattice relaxation during the mixing period affects the intensities of the sine and cosine arrays unequally Use of N other than 1 corrects for unequal relaxation times Set N to zero the antidiagonal of the 2D spectrum taul is the delay in microseconds between pulses p1 and pw of the quadrupole echo pulse sequence tau2 is the exact see NOTE below delay in microseconds between the second pulse and acquisition set the value of tau2 to less than tau1 to begin acquisition before the echo use 1sfid greater than 1 to begin the Fourier transform at the echo peak see below NOTE The delay to compensate for filter group delay controlled by parameters alfa beta and fb is not present in WLEXCH1 Adjust tau2 or use 1sfid to set the beginning point of the Fourier transform References Schmidt C Blumich B Spiess H W J Magn Reson 1988 79 269 Blumich B Spiess H W Angew Chem Int Ed Engl 1988 27 1655 6 26 CRAMPS Combined Rotation and Multiple Pulse Spectroscopy Multiple pulse sequences differ from other NMR experiments in how and when the evolution of the spin system is detected Ordinarily a short B pulse is used to move the magnetization from the Z direction to the X Y plane where it is detected as the spin system evolves in response to various interactions J coupling d
39. 30 Chapter 2 CP MAS Solids Operation xpol y pw levelt vere p2 p3 Figure 10 Rotating Frame Spin Lattice Relaxation Measurements Sequence xpol y level2 p1 pw level1 d1 d2 p2 Figure 11 Pulse Sequence for Measuring H T 2 11 Spectral Referencing 31 A variety of methods are found in the literature for spectral referencing Some involve a small sealed capsule of TMS centered in the sample Others use a small piece of polyethylene as a secondary reference For most purposes primary and secondary referencing are not necessary and external secondary spectral referencing can be used as follows 1 Insert a standard sample e g HMB 2 Obtain a spectrum and set spectral referencing For HMB set the cursor on the aromatic line and enter r1 132 1p 3 Adjust the display window as desired for BC enter wp 200p sp 0 4 Remove the standard sample and insert the sample of interest Obtain a spectrum Both field drift and field shifts affect this type of referencing Field drift is typically small and can be ignored Field shifts due to magnetic susceptibility effects are finite but small Chemical shifts measured as described above are in all cases reasonable but for a series of similar compounds the relative chemical shifts are even better For most purposes this procedure should be followed only at the time the probe is installe
40. 6 24 SSECHO1 Solid State Echo Sequence for Wideline Solids older parameter sets ssechol creates it and sets it to the value of tpwrf If tpwrf is not present tpwrm is set to 4095 The default parameters provide for a quadrupole echo with a pulse delay of 20 microseconds uTYINOVA and UNITY p us Power Parameters ssechol makes use of the generic power parameters tpwr tpwrm dpwr dpwrm and pw for YNTYTNOVA and UNITYplus systems These parameters have a consistent definition in most UNTYINOVA and UNITYplus single resonance i e wideline and CRAMPS pulse sequences They are also consistent with the parameters of xpolar1 with xpol n with the exception that the parameter dipolr replaces dpwrm in xpolar1 as the decoupler linear modulator voltage level tpwr is the observe power setting 16 dB minimum to 63 dB maximum power tpwrm is the observe linear modulator voltage setting 0 minimum to 4095 maximum voltage The value of tpwrm is linearly proportional to the applied signal voltage Doubling t pwrm halves the value of the pulse width dpwr is the decoupler power setting 16 dB minimum to 63 dB maximum power dpwrm is the decoupler linear modulator voltage setting during acquisition 0 minimum to 4095 maximum voltage dpwrm is linearly proportional to the applied decoupler voltage Doubling dpwrm doubles the decoupler field strength in kHz pw is the observe 90 pulse in microseconds Other Parameters echo set to y i
41. 6 HETCORCP1 Solid State HETCOR 69 HETCORCP1 is a H 3C heteronuclear chemical shift correlation HETCOR experiment for solid state materials Analogous to solution state HETCOR experiments this sequence provides correlation between H and 3C chemical shifts The HETCORCP1 experiment differs from the solution state HETCOR in that correlation depends on dipolar interactions rather than J coupling Applicability HETCORCP1 is available on UNYINOVA UNITYplus and UNITY systems It is found in psglib VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 7 WISE1 Two Dimensional Proton Wideline Separation Macro The macro het corcp1 converts a parameter set obtained with XPOLAR or XPOLARI for the solids HETCOR experiment HETCORCP1 Power levels and the proton 90 pulse width are retained Default parameters set up for a phase sensitive hypercomplex data set acquisition The correct sw1 is calculated and srate is set to the preferred value Set the actual spin rate equal to srate A single decoupler offset dof is used throughout Parameters hetcorcp1 uses the Y TYJNOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters setup is set to n to obtain a 2D spectrum normal operation Set setup y to obtain a single t FID blew is the number of BLEW 12 cycles You may use set up set to y to obtain a one dimensional spectrum using
42. 9162 00 A0800 VNMR 6 1C User Guide Solid State NUR 106 Chapter 6 Solid State NMR Experiments tau is the interpulse delay in microseconds that includes pw The CORY 24 cycle is 36 tau long and is repeated np 2 times to build up the FID np is the number of points acquired trigissetto y or n depending on the system On UN YINOVA and UNITYplus the pulse sequence in not tied to any internal triggering mechanism and t rig should always be set to n On UNITY and VXR data acquisition is triggered to an internal 500 kHz clock so trig must be set to y and the signal of the 500 kHz clock plugged into the external trigger input located on the Pulse Sequence Controller board tauc is the cycle time recalculated each time tau is changed Altering t auc does not have any effect on the experiment mp at is the true acquisition time based on np and tau mp_at is recalculated each time np or tau is changed Altering mp_at does not have any effect on the experiment References Cory D G J Magn Reson 1991 94 526 Barbara T M Baltusis L J Magn Reson 1994 106 182 6 33 MREVCS Multiple Pulse Chemical Shift Selective Spin Diffusion Figure 52 shows the diagram of a novel experiment called MREVCS developed by Spiess and coworkers that involves a multiple pulse selection of IH magnetization based on chemical shift differences during the mixing time IH spin diffusion during a mixing time and high resolution 13C CP MAS
43. 986 3 FLAGS phase2 0 nt 1 ai cdc ph phaser 0 ct 1 Figure 13 Real Channel FID Pattern 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NMR 46 Chapter 4 CRAMPS Multipulse Module Operation 5 Count the number of points in one cycle of the FID and the reestimate pw for a 90 pulse from the relationship pw pw 4 n where n is the number of points in one cycle 6 Repeat the acquisition adjusting pw and then tpwr to get approximately a 1 5 us 90 pulse 7 Enter gf then connect the acqi window Select FID and then IPA Adjust tpwrf until a pattern similar to Figure 14 is obtained This occurs at the exact 90 pulse Figure 14 FLIPFLIP FID at Exact 90 Pulse For further information on the FLIPFLIP pulse sequence refer to page 100 4 3 Running the FLIPFLOP Pulse Sequence 47 To run the FLIPFLOP pulse sequence rather that the FLIPFLIP pulse sequence set phase2 2 This train of pulses alternately flips the spins into the XY plane giving an NMR signal and back to the Z axis giving no NMR signal This sequence is used for other adjustments in most CRAMPS Multipulse spectrometers but because of the phase shifting circuit used in the UNTVINOVA and UNITYplus systems this sequence is only used to remove phase glitch caused by asymmetric phase transients at the beginning and end of each pulse The resulting FID of the FLIPFLOP pulse sequence appears as a set of tram tracks as shown in Figure 15
44. D Nutation 20 0 0 esssssesseseseoesececoneseecoeescesseesseesseessesneeseees 113 avaduuudasdeyudaaduasaug suai sdussau addsansuaadoueybauscubsauusaduasaddusaubususuudauasddusuwascuauadeued 116 5 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 List of Figures Figure 1 Linear Attenuator Control Graph 0 eee ee eeeseseceeeceeesseeeeseceecseeseesecaecaeesesaecaseeeeaeeaeeees Figure 2 Typical MAS Spectrum of Adamantane o ees eeseceseeeeeeceeceeeeeesecaeceeeseeaecaseeeeaesaeeees Figure 3 Tools for Coarse Adjustment of Sample Angle oo cei ceceecseseeeeceeeeeeseceeeeeeaeeaeeees Figure 4 FID Display of KBr on Angle EEN Figure 5 FID Display of KBr 1 2 Turn Off Angle oo ieee eeeseceeeceecneeeeesecneceeesesaecaeeeesaeaeeees Figure 6 Typical Hexamethylbenzene HMB Spectrum 0 cece eeeeeeseseeeeeeeceeeeeeeeaecateeeeaeeaeenes Figure 7 Array Of Contact Times missions ees Pruan eege ENEE eR EEE EEE SAER na Figure 8 TOSS Experiment on Alanine Spectrum and Sequence 0 cceeeeseseeseeseceeeeeeeeeeeees Figure 9 Protonated Carbon Suppression of Alanine Spectrum and Sequence 0 0 0 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 31 Figure 32 Figure 33 Figure 34 Figure 35 Figure 36 Figure 37 Fig
45. D1 Waveform Modulated Cross Polarization page 72 6 10 VACP Variable Amplitude Cross Polarization page 74 6 11 XPOLEDIT1 Solids Spectral Editing page 76 6 12 3QMAS I Triple Quantum 2D for Quadrupole Nuclei page 77 6 13 PASS1 2D Sideband Separation for CP MAS page 78 6 14 CPCS Cross Polarization with Proton Chemical Shift Selection page 80 6 15 CPCOS YPS Cross Polarization Phase Sensitive COSY page 81 6 16 CPNOES YPS Cross Polarization Phase Sensitive NOESY page 82 6 17 R2SELPULS 1 Rotation Resonance with Selective Inversion page 84 6 18 DIPSHFT 1 Separated Local Field Spectroscopy page 85 6 19 SEDRA2 Simple Excitation of Dephasing Rotational Echo Amplitudes page 87 6 20 REDOR 1 Rotational Echo Double Resonance page 89 6 21 DOUBLECP1 Double Cross Polarization page 91 6 22 T1CP1 T1 Measurement with Cross Polarization page 92 6 23 HAHNCP 1 Spin 1 2 Echo Sequence with CP page 93 6 24 SSECHO1 Solid State Echo Sequence for Wideline Solids page 95 6 25 WLEXCH 1 Wideline Solids Exchange page 97 6 26 CRAMPS Combined Rotation and Multiple Pulse Spectroscopy page 98 6 27 FLIPFLIP 90 Degree Pulse Calibration page 100 6 28 FLIPFLOP Phase Transient Removal page 101 6 29 HS90 90 Degree Phase Shift Accuracy page 102 6 30 MREV8 Cycled MREV8 Multiple Pulse Line Narro
46. MAS solids module Chapter 3 Wideline Solids Module Operation covers using the wideline solids module Chapter 4 CRAMPS Multipulse Module Operation covers using the CPAMPS multipulse module Chapter 5 Solid State NMR Accessories covers using the rotor synchronization rotor speed controller accessory and solids variable temperature accessories Chapter 6 Solid State NMR Experiments is a guide to more than 40 pulse sequences useful for performing solid state NMR experiments Notational Conventions The following notational conventions are used throughout all VNMR manuals Typewriter like characters identify VNMR and UNIX commands parameters directories and file names in the text of the manual For example The shutdown command is in the etc directory The same type of characters show text displayed on the screen including the text echoed on the screen as you enter commands during a procedure For example Self test completed successfully Text shown between angled brackets in a syntax entry is optional For example if the syntax is seqgen s2pul lt c gt entering the c suffix is optional and typing seqgen s2pul cor seqgen s2pul1 is functionally the same Lines of text containing command syntax examples of statements source code and similar material are often too long to fit the width of the page To show that a line of text had to be broken to fit into the manual the line is cut a
47. N YINOVA and UNITYplus It is found in userlib Macro The macro wlexch1 converts a solids parameter set obtained with SSECHO1 to the WLEXCHI spin I 1 solids exchange experiment Power levels and pw are retained If tpwrm is not present as in many older parameter sets wlexch1 creates it and sets it to the value of tpwrf If tpwrf is not present tpwrm is set to 4095 It is recommended that you set the 90 pulse pw with tpwrm use s2pu11 and obtain a quadrupole echo spectrum use ssecho1 before running wlexch1 The default parameters provide a mixing period of zero and quadrupole echo pulse delay of 60 microseconds Figure 45 is a diagram of the WLEXCH1 pulse sequence pw magic magic pw d d2 mix tau1 tau2 i at A B Cc Figure 45 WLEXCH1 Pulse Sequence 97 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 26 CRAMPS Combined Rotation and Multiple Pulse Spectroscopy Parameters wlexch1 makes use of the N YJNOVA and UNITYplus parameters tpwr tpwrm dpwr dpwrm and pw See page 95 for a description of these parameters wlexch1 is based on the quadrupole echo pulse sequence ssecho and tau1 and tau2 have similar definitions pw is the observe 90 pulse in microseconds pulses 1 and 4 of WLEXCH1 magic is a 54 7 pulse in microseconds pulses 2 and 3 of WLEXCH1 mix is the mixing period in seconds for development of the elliptical ridges due to molecular motion phase is set to
48. The adjustment to remove phase glitch is done either at the probe or at the 1 kW high band amplifier After setting phase2 2 enter gf and then interactively observe the FID using the acqi window If the FID shows a sine wave in the tram tracks carefully adjust the probe tune or match to remove it If this cannot be done carefully adjust the 1 kW amplifier tune or load The desired result is shown in Figure 16 Finally set phase2 0 and repeat the pw90 determination as outlined above using the FLIPFLIP process No re examination of gating is required but the 90 pulse should be set as precisely as possible VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 4 4 Using MREV8 to Demonstrate Multipulse Operation ACQUISITION SAMPLE PROCESSING FLAGS sfrq 399 952 date Apr 1 93 lb not used LL n tn H1 file exp sb not used in n np 128 DECOUPLING gf not used dp y SW 2e 06 dn H1 awc not used trig y fb 1e 06 dof 0 lsfid 0 SPECIAL bs 16 dm n phfid not used srate 1542 ss 0 dpwr 30 fn 4096 temp 27 0 tpwr 54 tpwrf 2794 werr tauc 10 000 pw 1 400 wexp dE mp at 0 000640 tau 10 000 wbs dl 4 000 wnt phasel 0 tof 2986 3 FLAGS phase2 0 nt 1 ai cdc ph phaser 65 7 ct 0 Figure 15 FLIPFLOP Tram Tracks Figure 16 FLIPFLOP Desired FID For further information on the FLIPFLOP pulse sequence refer to page 101 4 4 Using MREV8 to Demonstrate Multipulse Operation The MREV8 pulse sequence demonstrates the operation of the multipulse sy
49. Typical Ranges Gain Setting Typical Ranges Gl 4to5 G2 1to2 55 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 5 4 Variable Temperature Operation with Solids Gain Setting Typical Ranges G3 0 G4 0 G5 0 5 to 1 with a loop delay of 500 to 700 ms and an increment clamp of 5000 The configuration parameters can be saved to a file on the PC e g gain set Upon initial startup the parameters in this file are loaded in order to set the configuration Be sure to make copies of the configuration parameters file gain set or write down the current settings if you wish to experiment with changing the rotor control configuration Additional Operation Note The PC computer has been set up such that a monitor and keyboard is not required in order to pass the POST Power On Self Diagnostics test which occurs before the operating system is loaded from disk These options are set into the CMOS BIOS setup at the factory If the CMOS fails for some reason the BIOS setup will have to be reconfigured The most likely cause for CMOS failure is drainage on the battery that powers the CMOS when the computer is off This battery is continuously recharged while the computer is on so even if the rotor speed controller is not in use it is wise to keep the computer powered up If the computer does need to be turned off do not leave it off for extended periods of time weeks or months If the CMOS does lose its memory setti
50. a proton chemical shift selection pulse or to observe the pulse sequence with dps for ni greater than 1 pw is both the H 90 pulse and the 13C 90 pulse the pulses must be equal Adjust tpwrm using xpwxcal to make the pulse lengths equal wim is the number of WIM 24 cycles used for cross polarization For best results set the length of the WIM 24 cross polarization to occupy one half a rotor period for example wim 1 pw 4 0 and srate 5208 yields 96 microseconds of CP and a rotor cycle of 192 microseconds srate is the actual rotor speed see wim above It is preferable but not necessary to use rotor speed control bmult is the number of BLEW 12 cycles per fy dwell time Set parameter sw1 to the value 1 0 obmult 12 pw 1le 6 Default values are bmult 2 for phase 1 2 hypercomplex alternatively bmult 1 for phase 3 TPPI phase 1 2 for the hypercomplex method use wft 2da for the 2D FT phase 3 for TPPI use wft2d 1 0 0 0 for the 2D FT dipof2 issetto y to use a second decoupler offset during acquisition dof determines the f offset which may be set above or below the IH chemical shift region if a pedestal is present in f In this case set dipoff for the center of the H shift region for best decoupling dipof2 is set to n to use dof during the evolution period and decoupling Reference Bielecki A Burum D P Rice D M Karasz F E Macromolecules 1991 24 4820 6 7 WISE1 Two Dimensional Pro
51. abled as cppwr with dblv12 y Other parameters have been given more descriptive names as described below Applicability XPOLARI is available only on NYINOVA and UNITYplus systems and can be found in psglib VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 2 XPOLAR1 Cross Polarization HNTVuNOVA amp UNITYplus cntct towrm at Tx pw cntct dipolr crossp d1 Dec hb A c Figure 25 XPOLARI1 Pulse Sequence Macro The macro xpolar1 converts parameters for XPOLAR and most other double and triple resonance solids pulse sequences for the XPOLAR1 pulse sequence Power parameters are left unchanged Parameters irrelevant to XPOLARI are removed If the UNITY power parameters are defined in an XPOLAR parameter set they are converted to the corresponding UN TYINOVA and UNITYplus parameters levell cppwr level2 dpwr levellf crossp level2f dipol p2 cntct tpwrf tpwrm and dblv12 is setto y Note that xpolar1 does not convert an arbitrary parameter set for solids First retrieve a solids parameter set e g xpolar par in the VNMR directory par1ib and then convert it with the xpolar1 macro Parameters The following parameters have consistent definition throughout all 4 YZNOVA and UNITY plus solids pulse sequences Most sequences other than XPOLAR and XPOLARI assume xpol y for cross polarization and xpo1 is not settable e xpolissetto n for direct
52. ack the rotor a mortar and pestle is usually sufficient Fluffy or flaky materials can be packed with a rod machined to a slightly smaller diameter than the internal diameter ID of the rotor Hand pressure should be sufficient Hard packing with a press or hammer is not necessary and can damage the rotors The cap works best if it is in contact with the top of the sample material and fits snugly and flush with the top of the rotor Miscellaneous Materials Many different sample types and forms exist that are neither machinable solids nor granular or powdered materials Some of these materials can be prepared in rotors so that dynamic balance is preserved while others cannot Basically if the material can be made to fill the rotor homogeneously chances are good that it will spin adequately Thick sheet or film materials are best handled by cutting or punching many disks each having the inside diameter of the rotor and stacking them in the rotor until full Coarse and irregular granular materials as well as pellets beads flakes bits or pieces often cannot be packed homogeneously enough to provide the balance necessary for high speed spinning Sometimes such materials can be made to spin smoothly by filling the voids with a fine powder that does not give NMR signals such as KBr talc or sulfur flowers and spinning at a lower speed CAUTION Organic solvents can dissolve pMMA end caps Liquid Samples For liquid samples use an end c
53. alling edge to falling edge is lt 500 ns for spinning speeds to 8 kHz This corresponds to an angular uncertainty of lt 0 5 at a spinning speed of 3600 Hz An edge is detected normally as the negative going transition of the reflected light going from at least a value of 39 dBm to no more than 45 dBm measured at the end of the fiber optics CAUTION Never spin PSZ zirconia rotors white or off white in color above 7 5 kHz or silicon nitride rotors gray above 9 kHz High spinning speeds will cause the rotors to shatter Doty Scientific Probe Jitter in a TTL rotor period is lt 2 us for spinning speeds to 5 kHz This corresponds to an angular uncertainty of lt 2 at a spinning speed of 3600 Hz This is expected over the temperature range of 50 C to 100 C provided that the tachometer amplifier gain is correctly adjusted to give a signal of no less than Vpp into the tachometer box 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 52 Chapter 5 Solid State NMR Accessories 53 Using Rotor Synchronization Table 6 lists parameters used with the rotor synchronization accessory Table 6 Rotor Synchronization Controls Parameters hsrotor y n Display rotor speed for solids operation in y nl Interlock srate 0 107 in Hz Spinning rate for magic angle spinning The rotor synchronization accessory can be used in a number of ways from simple monitoring of spinning speed to sophistic
54. amp 1 0 frac 2 0 frac 2 0 1 0 4 0 t per for per 2 0 lt t lt per The resulting DEC file has the form xmodramp_frac_per_amp DEC where frac is x10000 and per is in microseconds The defaults are per 1 srate and amp 1023 amp is the amplitude of the waveform amp 1023 VNMR 5 1 and later software provide scaling of amp with the value of crossp or tpwrm For earlier versions set amp to its fixed value during the pulse sequence lt 1023 where amp 1023 is a full amplitude of the linear modulator frac is the fraction of modulated intensity a value between 0 and 1 0 per is the period of cosine modulation for 0 to 27 radians For a ramp the slope is negative 1 4t per for t 0 to per 2 and positive 1 4t per fort per 2 to per Set per relative to cntct to obtain a specific shape or ramp during the contact time References Hediger S Meier B H Ernst R R Chem Phys Lett 1993 213 627 6 10 VACP Variable Amplitude Cross Polarization As typical field strengths and rotor speeds used for CP MAS increase a problem that develops is the rotor speed dependence of cross polarization Usually signal to noise drops and the zero speed Hartmann Hahn match splits into a set of sidebands A straight forward solution is to vary the pulse amplitude during the contact time of the cross polarization A set of alternating amplitudes with an increasing difference during the contact time is quite effective in removing
55. ample Preparation The main requirement is that the sample be no longer than 25 mm nor greater than 5 mm in diameter Samples must fit into the coil of the probe and be electrically insulated from the coil The most convenient sample carrier is a 15 mm length of 5 mm outside diameter NMR tube which can be sealed with Parafilm or some other background free material For best results the sample should be kept small in comparison with the length of the coil and VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 3 4 Data Acquisition should be placed symmetrically in the coil when in the probe Remember that the NMR tube has a 29Si 8Na 27Al and 11B background signal WARNING Dangerous high voltage exists inside the probe that can cause burns or serious injuries Follow the instructions below to avoid the hazard When changing samples take the following precautions e Set the HI POWER ENABLE switch to OFF e Disconnect the transmitter cable from the probe e Be especially careful of damaging the coil supports when inserting or removing a sample from the coil as well as when changing coils These supports are fragile and can be easily damaged Shimming Because of the width of the resonances encountered in wideline work shimming is rarely necessary or possible on each sample The following approach is typical 1 When the probe is first installed insert a sealed sample of D20 in the probe for shimming purposes 2 Tune the
56. amples were generally characterized by broad featureless envelopes caused by additional nuclear interactions present in solid state In liquid state these interactions average to zero due to rapid molecular tumbling 1 1 Line Broadening One cause of line broadening is heteronuclear and homonuclear dipolar coupling This coupling arises from the interaction of the nuclear magnetic dipole under observation with those of the surrounding nuclei and is directly proportional to the magnetogyric ratios of the nuclei and inversely proportional to the distance between them In strongly coupled organic solids the heteronuclear dipolar coupling between a 13C nucleus and a bonded proton can be 40 kHz In order to remove the heteronuclear dipolar coupling a strong rf field equal to or greater than the interaction energy must be applied at the proton resonance frequency A second cause of line broadening in polycrystalline compounds is chemical shift anisotropy CSA This is the result of nuclei with different orientations in the applied magnetic field resonating at different Larmor frequencies The observed spread of the chemical shifts is called the chemical shift anisotropy and can be as large as a few hundred ppm This interaction can be removed by rapidly rotating the sample about an axis oriented at an angle of 54 degrees 44 minutes 54 73 the magic angle in magic angle spinning or MAS to the applied magnetic field The spinning speed of the sa
57. ance pulse sequences 96 SLF experiment 85 sodium nitrate sample 41 wideline experiments 39 solid echo experiments 39 sequence 95 solids 2D exchange correlation experiment 82 analysis software accessory 34 95 cabinet 36 exchange experiment 97 01 999162 00 A0800 Index high power amplifiers caution 11 homonuclear correlation experiment 81 sample removal 21 solid state chemical exchange 68 NMR experiments 59 spectra 14 specifications for rotor sync accessory 52 spectral editing 76 referencing methods 31 resolution 28 speed control process 55 spin diffusion 109 echo mode 43 locking pulse 59 quantum number 38 rate adjustment 21 54 rates 21 spindiff macro 109 SPINDIFF pulse sequence 109 spin lattice relaxation time 15 59 61 measurements 30 spinning sideband suppression 28 60 65 speed dependence of cross polarization 74 troubleshooting 21 srate parameter 28 29 53 60 62 65 70 82 84 85 87 91 SSECHO pulse sequence 95 ssecho pulse sequence 39 ssechol macro 95 SSECHO1 pulse sequence 95 standby button 37 STARS 77 static lineshape for spin 1 2 powder spectra 93 magnetization 99 status panel for high power amplifiers 37 sum to memory STM circuitry 34 swl parameter 111 sync module 44 45 sync parameter 67 83 T T measurement 92 tlcp parameter 93 T1CP1 pulse sequence 92 tlinc parameter 109 tlinit parameter 109 tachometer box 52 53 sensing 20
58. ap that has a concentric hole drilled through it a 73 drill is recommended Be sure the end cap will not dissolve organic solvents can dissolve pMMaA end caps Liquid samples can be spun at several hundred Hz but the liquid may spin out of the rotor and be lost This fact must be considered when dealing with toxic or noxious samples VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 3 Spinning the Sample 2 3 Spinning the Sample On Varian high speed rotors tachometer sensing is on the rotor bottom Zirconia rotors are marked with a permanent black marking pen or black enamel so that 50 of the bottom of surface area is shaded black silicon nitride SizN 4 rotors are marked with white enamel in the same fashion Centrifugal force can cause the black and white markings to flake off around the edges This can cause inaccurate tachometer readings The black or white half circle can be reapplied on the rotors with a black marking pen and white correction fluid The diameter marking should be straight Doty high speed rotors have optical markings inside the bottom cap other Doty probes use electrostatic sensing triboelectric See the Doty manual for instructions on reapplying the optical marking WARNING A projectile hazard exists if a spinning rotor explodes To prevent possible eye injury from an exploding rotor avoid spinning rotors outside the magnet If it is necessary to spin a rotor outside the magnet use a certified
59. ated synchronized experiments In all cases the accuracy of the readout is dependent on the marking of the sectors on the rotor Figure 19 shows the marking on the base of Varian high speed spinning rotors and Figure 20 shows the marking inside the lower rotor cap for Doty rotors Rotor Markings For Varian high speed spinning rotors the base of zirconia rotors may be blackened using a black permanent marker Make sure that the dividing line across the diameter is clear and that the black sector is solid black The base of silicon nitride rotors may be whitened similarly using typewriter correction fluid Avoid using a water based correction fluid because it is more likely to spin off the rotor White paint can also be used For Doty rotors use the supplied black and white paints Ensure that the dividing line between black and white is sharp Periodically check that the black and white markings are still sharp Over time the high spinning speeds may cause the paint to fly off Repaint the rotors when needed Sample Spinning The sample is packed in the rotor in the normal way The rotor is spun in accordance with the instructions in Spinning the Sample page 20 and the spinning speed may be read on the tachometer box LCD display Note that for Varian probes the optical fibers should be plugged into the tachometer box and for Doty probes the probe should be connected to the Doty tachometer amplifier the switch on the amplifier se
60. be disconnected at the AR front panel e To operate in the pulsed mode press the OPERATE button to set the amplifier in the standby mode Press the PULSED button then the OPERATE button once again The amplifier is now in the pulsed mode with pulse gating not noise blanking The maximum rated power output in the pulsed mode is 1 kW 60 dBm This should not require adjustment of the amplifier gain e To return to the continuous mode switch back to the standby mode by pressing the OPERATE button followed by powering off the amplifier The AR amplifier has been calibrated at 100 MHz so that when its front panel gain control is set to the marked position and the manual attenuators are set to 0 the power output is equal in dBm to the value of t pwr in other words tpwr 60 delivers 1 kW 60 dBm and tpwr 50 delivers 100 W 50 dBm This calibration may not be precise at other frequencies but provides a first approximation AMT Linear Amplifier The AMT linear amplifier is gated off whenever the receiver is gated on A time of at least 8 us is required for the bias to come on fully and thus for the amplifier to provide full output power Allowance for this time delay must be made in any pulse sequence programming using rofl The maximum pulse width is 20 ms at full output and with a maximum duty cycle of 10 The AMT amplifier is fully protected against thermal overload and it indicates excessive duty cycle and excessive pulse width Status
61. ble for all UNITY systems and can be found in the userlib The default parameters of the setup macro are applicable for only YNTYZNOVA and UNITYplus The processing parameter das 1p is present in VNMR 5 2 and later The 3QMAS1 experiment requires only MAS hardware and in many circumstances this method can replace the need to do the more complicated experiments double rotation DOR and dynamic angle spinning DAS 3QMAS1 is a robust experiment that is well worth trying before contemplating the use of DOR or DAS Macro The macro s3qmas1 converts a parameter set for the triple quantum MAS experiment 3QMAS1 pw3q is set to 180 pulse length the minimum practical pulse length needed to excite triple quantum coherence with the assumption that pw is the 90 pulse length If tpwrm is not present as in many older parameter sets 3qmas1 creates it and sets it to the value of tpwrf If tpwrf is not present tpwrm is set to 4095 The default is pws 0 0 for no refocusing pulse and sw1 sw The macro s3qmas1 creates the processing parameter das1p used for shearing applicable for VNMR 5 2 or greater VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 13 PASS1 2D Sideband Separation for CP MAS Parameters 3QMAS1 makes use of the YNTYZNOVA and UNITYplus parameters tpwr tpwrm dpwr dpwrm and pw See page 95 for a description of these parameters pw is the observe 90 pulse in microseconds for a solution state sample of the quadrupole
62. cceptable duty cycle sync setto y is used with rfdr y to provide dipolar recoupling during the mix period sync set to n provides the usual NOESY mixing period rfdr setto y set sync y sets the mixing period to a multiple of 8 rotor periods close to the value of mix The rotor period is obtained from the value of srate 7 pulses VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 17 6 17 R2SELPULS1 Rotation Resonance with Selective Inversion are applied at the middle of each rotor period with the phase cycle xy8 to cause dipolar recoupling rfdr set to n sets the mixing period equal to the value of mix and pulses are not applied srate is the actual spinning speed CPNOESYPS with rfdr y requires rotor speed control Reference Bennett A E Ok J H Griffin R G Vega S J Chem Phys 1992 96 8624 R2SELPULS1 Rotation Resonance with Selective Inversion The R2SELPULS1 pulse sequence is used for the rotational resonance experiment with a selection inversion pulse of Griffin and coworkers Figure 37 is a diagram of the sequence cntct pwx pwx tpwrm p1 towrm2 mix at Tx pw cntct dipolr crossp Dec al A Cc B Cc Figure 37 R2SELPULS1 Pulse Sequence Rotational resonance r is obtained between nuclei coupled by the through space dipolar interaction when the chemical shift difference between the resonances is an integral
63. ce 32 refocus parameter 87 refocusing pulse 87 relaxation measurements 95 relaxation rates 38 relief valves warning 10 removable quench tubes warning 10 repetition rate 27 28 repolarization 76 resonances is selectively inverted 84 Return key 12 rfdr parameter 83 rofl parameter 36 37 45 rof2 parameter 45 rotating frame 30 spin lattice relaxation time 61 01 999162 00 A0800 rotation period of a rotor 50 Rotational Echo Double Resonance 89 rotational resonance 84 rotor crashing in VT solids 57 explosions 21 on CRAMPS probe 45 periods 86 speed control 69 synchronization 33 50 rotor speed 70 84 controller accessory 54 dependence of cross polarization 74 display 54 read out 50 rotors for solids 18 rotorsync option 67 rotor synchronization accessory 69 rotor synchronized CP MAS exchange sequence 68 S s3qmas1 macro 77 safety precautions 8 10 sample placing solids in the rotor 18 plug removal 19 spinning 54 wideline experiments 39 sapphire rotors 18 scalesw macro 100 sector markings 52 SEDRA cycles 88 pulse sequence 87 sedra2 macro 87 sedraflag parameter 88 sense parameter 87 separated localized field spectroscopy 85 setref macro 32 setup parameter 70 86 shift parameter 109 shimming wideline experiments 40 sidebands 60 silicon nitride rotors 18 20 21 52 Simple Excitation of Dephasing of Rotational Echo Amplitudes 87 single transient 20 single reson
64. ces using rotor sync elements refer to the VVMR User Programming Manual for information on creating pulse sequences 5 3 Rotor Speed Controller Accessory Operation The Varian rotor speed controller accessory provides computer control of the spin rate of a CP MAS sample By using the controller in a closed loop mode the sample spinning rate can be held constant to a few hertz or better over a long acquisition time days or weeks During variable temperature operation the rotor controller can keep the spin rate from changing while varying the operating temperature The setting of a desired rate is much easier because fine control is provided for and slow drift is automatically compensated Rotor Speed Controller Hardware The rotor speed controller accessory consists of the following hardware e Modified Varian VT pneumatics tachometer box e PC compatible computer with 16 bit timer counter and DAC cards e Cabling to connect PC pneumatics tachometer box and Sun workstation The use of a PC computer provides an inexpensive powerful and dedicated processor for rotor speed controlling tasks The PC houses 16 bit DAC and counters for measuring the rotor speed and supplying a 0 to 5 V signal to the pneumatics transducer inside the pneumatics tachometer box Operator control of the PC and software takes place through a RS 232 link to the Sun host computer Rotor Speed Controller Software The rotor controller is run with the rcont rol software
65. cycle is 64 transients The synched experiment requires SSBs to be present so the spin rate should be slow enough Because the mix time is recalculated on the basis of the number of integral rotor periods that is nearest to the desired mix time mix will not be exactly correct The correct value is calculated and printed at go time Normally the sync experiment is run as a P type experiment Process the data with sinebell weighting wft2d ptype and foldt References Szeverenyi N M Sullivan M J Maciel G E J Magn Res 1982 47 462 DeJong A F Ketgens A PM Veeman W S Chem Phys Lett 1984 109 337 6 5 MASEXCH1 Phase Sensitive Rotor Sync Sequence for Exchange MASEXCH1 is a rotor synchronized CP MAS exchange sequence similar to XNOESYSYNC except that this sequence can yield a phase sensitive spectrum rather than an absolute value plot This experiment should be run under slow spinning conditions since spinning sidebands intensities carry the information A normal MAS spectrum including sidebands is obtained along the diagonal Cross peaks appear when solid state chemical exchange or molecular reorientation is present Figure 28 is a diagram of the sequence sync y mix n srate for phase 1 2 mix n srate d2 for phase 3 4 cntct pwx pwx crossp A C Figure 28 MASEXCH1 Pulse Sequence 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 68 Chapter 6 Solid State NMR Experiments
66. d The 3C chemical shifts of a few reference materials are given in Table 3 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 12 Further Reading on Solid State NUR The set ref command adjusts referencing so that the solvent frequency is correct even when no reference substance is present in the Table 3 Reference Materials and 3C Chemical Shifts sample Substance Chemical shift ppm setref uses absolute resonance adamantane 29 2 38 3 frequencies as defined in a file delrin 88 5 vnmr nuctables nuctabref glycine 43 6 176 4 currently about 25 of the most hexamethylbenzene 17 3 132 1 common nuclei are covered in this file poly methyl 19 45 51 176 setref can easily be expanded to methacrylate cover any other nucleus as well a tale Cie on recipe on how to expand set ref is given in the header of the file vnmr nuctables nuctabref 2 12 Further Reading on Solid State NMR General Sources on Line Narrowing in Solids Gray G A Hill H D W Industrial Res and Dev 1980 March Miknis F P Bartuska V J Maciel G E Am Lab 1979 November Griffin R G Anal Chem 1977 49 951A Fyfe C A Solid State NMR for Chemists CFC Press Guelph 1983 Cross Polarization Technique Pines A Gibby M G Waugh J S J Chem Phys 1973 59 569 Stejskal E O Schaefer J Waugh J S J Magn Reson 1977 28 105 Relaxation Times Schaefer J Stejskal E O Buchdahl R Macromolec
67. d intended use of the instrument Varian assumes no liability for customer failure to comply with these precautions CAUTION Keep magnetic media ATM and credit cards and watches outside the 5 gauss perimeter of the magnet The strong magnetic field surrounding a superconducting magnet can erase magnetic media such as floppy disks and tapes The field can also damage the strip of magnetic media found on credit cards automatic teller machine ATM cards and similar plastic cards Many wrist and pocket watches are also susceptible to damage from intense magnetism Refer to the manuals supplied with the magnet for the size of a typical 5 gauss stray field This gauss level should be checked after the magnet is installed 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 10 SAFETY PRECAUTIONS Caution Notices continued CAUTION CAUTION CAUTION Check helium and nitrogen gas flowmeters daily Record the readings to establish the operating level The readings will vary somewhat because of changes in barometric pressure from weather fronts If the readings for either gas should change abruptly contact qualified maintenance personnel Failure to correct the cause of abnormal readings could result in extensive equipment damage Never operate solids high power amplifiers with liquids probes On systems with solids high power amplifiers never operate the amplifiers with a liquids probe The high power available from these
68. d the resulting free precession generated by Hes does not produce real and imaginary components of equal magnitude Moreover the signal also contains large amounts of static magnetization often referred to as pedestals if the initial magnetization vector M 0 is not orthogonal to n Because of these peculiar features of multipulse NMR single phase data is often taken with the receiver phase oriented in such a fashion as to minimize their effects For MREV8 proper preparation pulses to eliminate pedestals were used from the outset since their implementation required only traditional quadrature phases Similar initializing pulses from BR24 have not been emphasized because of the necessity of 45 phase increments Since MREV 8 has an average Hamiltonian along 1 0 1 the magnetization trajectory after a 90 preparation pulse in degrees is an ellipse whose principal axes coincide with the rotating frame axis Depending on the given window chosen for sampling the major axis will be aligned along either the x or y axis of the rotating frame The minor axis is 1 2 of the major axis and this produces quadrature images as complex data points are sampled and processed with a complex FFT Quadrature Correction Quadrature correction can be produced by implementing a four step cycle where for each step the preparation pulse is chosen such that M 0 successively lies on the semimajor and semiminor axes of the ellipse That is the preparation pul
69. d1 pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw p1 dtau dtau tau dtau dau dtau dau dau dau dau dau dau tau dtau tau dtaupbw tau dtau dtau tau tau dtau tau dtau tau dtau tau dtau tau dtau tau dtau tau dtau tau dtau A Figure 50 Cycled CORY 24 Pulse Sequence 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 0 2u 53 gt gt 3SN ao aao ECH ECO EA EAR E alol Lee eise lols als o E a d Il Ill lge 1 0s st et st oO CH CH CH CH Ou CH CH CH CH Tx di pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pw pi dtau dtau dau dau dau dau dau dau dau dau dau dau tau dtau tau dtaljow tau dtau dtau tau tau dtau tau dtau tau dtau tau dtau tau dtau tau dtau tau dtau tau dtau A Figure 51 CORY24 Pulse Sequence Macros The macro cory24 converts a FLIPFLOP MREV8 or S2PUL parameter set into the CORY 24 line narrowing pulse sequence The macro cylcory24 converts the CORY 24 parameter set to that suitable to run Cycled CORY 24 No parameter changes are necessary the preparation pulse are based on the value of pw as described in Table 10 Parameters pw is the 90 pulse length in microseconds p1 is the preparation pulse in microseconds with phase controlled by phase1 To minimize the pedestal set p1 to the 90 pulse length and set the phase to 135 degrees by using the parameter phasel 01 99
70. delay in microseconds that includes pw The MREV8 cycle is 12 tau long and is repeated np 2 times to build up the FID np is the number of points acquired trigissetto y or n depending on the system On UN YINOVA and UNITYplus the pulse sequence in not tied to any internal triggering mechanism and t rig should always be set to n On UNITY and VXR data acquisition is triggered to an internal 500 kHz clock so trig must be set to y and the signal of the 500 kHz clock plugged into the external trigger input located on the Pulse Sequence Controller board tauc is the cycle time recalculated each time tau is changed For MREV8 the cycle is 12 tau long Altering tauc does not have any effect on the experiment mp_at is the true acquisition time based on np and tau mp_at is recalculated each time np or tau is changed altering mp_at does not have any effect on the experiment References Rhim W K Elleman D D Vaughan R W J Chem Phys 1973 59 3740 Barbara T M Baltusis L J Magn Reson 1994 106 182 BR24 Cycled BR24 Multiple Pulse Line Narrowing BR24 is one of several multiple pulse sequences that removes the strong homonuclear dipolar interactions allowing for pure chemical shift spectra to be obtained for H and Tip nuclei in the solid state Figure 49 is a diagram of the BR24 sequence Macros The macro br24 converts a FLIPFLOP MREV8 or S2PUL parameter set into the BR24 line narrowing pulse sequence
71. detection to study the mixing of components on a molecular scale This version is for H detection 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 0 2u 5 bel 1 0s 0 8u 0 8u 0 8u 4 3u 0 8u 3 5u 94 8u 0 8u 0 8u 4 3u 3 5u 3 CH 4 3u T3 0 8u 0 8u 4 3u 4 3u Tx di dau pw pw pw pw pw pw pw stau pw pw pw pw tau pw pw pw dtau dtau dtau pw dtau dtau pw dau dtau tau dtau tau dau tau dtau w tau tau dtau tau dtau tau dtau 2 0ef7 tau dtau A Figure 52 MREVCS Pulse Sequence Macro The macro mrevcs retrieves a parameter set suitable for the MREVCS experiment 107 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 34 MQ_SOLIDS Multiple Quantum Solids Parameters The parameters are analogous to those in all multiple pulse experiments pw is the 90 pulse in microseconds tau is the time delay in microseconds between pulses In the case of MREV8 the cycle time is 12 tau mix is the mixing time in microseconds for IH spin diffusion cycles is the number of times through the multiple pulse cycle cycles and tof in combination determine the chemical shift Reference Spiess H Schmidt Rohr K Clauss J Blumich B Magn Reson Chem 1990 28 S3 6 34 MQ_SOLIDS Multiple Quantum Solids Tx AH multipl
72. e is applied at the middle of each rotor period Usually cycles is an integer from 0 to the maximum number of cycles Typical values are 0 to 8 sedraflag set to n causes a 90 pulse to be applied at the middle of each 8 pulse SEDRA cycle This pulse partially refocuses the effects of SEDRA and provides a control If sedraflag is set to y a90 pulse is not applied allowing full SEDRA evolution Usually sedraflag is setto n y Fora simultaneous array of cycles and sedraflag set array to cycles sedraflag and not the reverse phaseflag is set to n for normal operation If phaseflag is setto y and sedraflag is set to n 90 pulses are applied with 180 phase alternation for 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 88 Chapter 6 Solid State NMR Experiments 6 20 89 successive SEDRA cycles Better refocusing of the control pulse sequence should lead to a larger SEDRA effect Caution setting phaseflag to y is not fully tested Reference Guillion T Vega J Chem Phys Lett 1993 194 423 REDOR1 Rotational Echo Double Resonance NMR measurement of internuclear distance by using multidimensional methods has been of great importance for the determination of biomolecular structures in solution It is desirable to obtain similar data from the solid state for study of membrane protein structures that have been largely inaccessible with solution state methods REDOR Rotational Echo Double R
73. e quantum spectrum can be obtained in the solid state in the manner of Pines and Baum The pulse sequence called MQ_SOLIDS generates even order multiple quantum transitions and detection uses the magic echo sequence Figure 53 is a diagram of the sequence 1 5u 1 5u 1 5u 1 5u 1 5u 1 5u 1 5u 1 5u 50 0u 1 5u 1 5u 1 5u 1 5u 1 5u 1 5u 1 5u 1 5u 50 0u 1 5u 1 0u 5 5 5 D gt fo fo e e ei e CH Les Les DO 3 ex Sr St 5 sf 5 ez O D DO sl Ko iO Ko O 3 0s Rr H lt kille 5 S KG E di pw pw pw pw pw pw pw pw ddel pw pw pw pw pw pw pw pipi ddel ddel ddel ddel mn ddel ddel ddel d3 pw ddelp ddelp ddelp ddelp pw ddelp ddelp ddelp p1 0 5 pw rgf2 ddelp Figure 53 MO SOLIDS Pulse Sequence Macro Macro mq_solids generates the parameters for the multiple quantum experiment Parameters del is the short interpulse delay in microseconds de lp is the long interpulse delay in microseconds 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 108 Chapter 6 Solid State NMR Experiments mloop is the number of times typically 7 through the first multiple pulse cycle shift is the TPPI phase increment The units of this parameter have not been fully checked Use the display command to confirm units t linc is the t increment in the convention of a 2D experiment The units of thi
74. e supplies are produced by a unit in the bottom of the cabinet behind the EHT The amplifier is tuned by three controls to the frequency at which it is to be used It is able to produce up to 1 kW output for periods up to 250 ms or lower levels for longer periods 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 44 Chapter 4 CRAMPS Multipulse Module Operation The amplifier runs in a linear mode and can be considered to be a gain stage added to the liquids high band amplifier The 1 kW stage operates in either blanked or unblanked modes in exactly the same manner as its low power driver It should never be driven by more than 50 W 47 dBm Three controls are used to tune the amplifier INPUT TUNING on the front of the amplifier and OUTPUT TUNE and LOAD on the remote motor control box When used for CRAMPS Multipulse in the observe transmit chain the amplifier is run blanked rather than unblanked as in CP MAS As a result sufficient unblanking time xof1 must be allowed for the amplifier to turn on The whole transmit amplifier chain requires a rof1 of 1 5 us for this The reblanking time is very short so that rof2 can be set to zero These timings ignore any probe ring down issues If the system is equipped with 6 dB fine attenuators tpwrf and tpwr must be set and used whether high power is selected or not Sync Module UNITY VXR S only The sync module located on the wideline receiver provides a buffered 500 kHz
75. e the real time FID display The FID displays a transient that is an exponential decay with a picket fence of one or more spikes on it see Figure 4 and Figure 5 If the signal is not exactly on EEN Figure 4 FID Display of KBr on Angle resonance adjust ZO until it is then select IPA and adjust phfid to maximize the on resonance FID 5 Adjust the angle using the appropriate method below e Varian RT CP MAS probes Turn the screw between the two copper coax lines in the probe baseplate e Varian VT CP MAS probe Turn the fiberglass rod with the adjustment tool e Doty CP MAS probe Turn the smaller gold rod 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 24 Chapter 2 CP MAS Solids Operation 25 Figure 5 FID Display of KBr 1 2 Turn Off Angle Maximize the size and number of spikes in the picket fence The spikes should persist for about 10 ms The sample angle is now set to the magic angle 6 Close the acqi window and retune the probe to the appropriate nucleus The same sample and general procedure can be used to monitor spinning stability both in angle and in speed An angular instability shows in two ways the shape and size of the exponential varies from transient to transient and the picket fence is unstable in length and amplitude if the rotor is vibrating Instability in the spinning speed can be measured by inspecting the summed FID If acquisition is continued for a time
76. ecause arrayed experiments cannot use Autogain and acquire the data Determine the 90 pulse width to 25 ns resolution Set pw and pw90 to the 90 pulse width value This completes the calibration procedure VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 3 5 Standard Wideline Samples 13 Replace the DO sample with the malonic acid d sample and tune the probe 14 Enter ssecho to convert the s2pu1 parameter set to one suitable for the SSECHO pulse sequence Set tau1l 20 tau2 15 nt 16 15 Set gain n and enter go to acquire data 16 Enter df to display the FID Use the phase button and the mouse to maximize the real cyan channel Set 1s id 0 Put a single cursor on the echo maximum and enter tmove Transform the FID 17 Phase correct the spectrum using rp only set 1p 0 Select two cursors and set each on top of a horn of the powder pattern Enter split to move the right cursor to half way between the two horns Entering movetof then sets the observe transmitter to this position 18 Reacquire data this time with d1 10 19 Enter df to isplay the FID Maximize the real channel as in step 16 and put a single cursor at the echo maximum putting it between data points if necessary This FID can either be transformed or data reacquired starting from the cursor position If the FID is to be transformed then enter tmove wft Phase correct the spectrum as before If new data is to be acquired starting at the cur
77. ecbsaesbesscisedeidasdtaccubnessbachonanseielbnencsegesbsnsseede cus 107 Figure 51 Cycled CORY 24 Pulse Sequence ENEE 108 Figure 52 CORY 24 Pulse Sequence eege deeg 108 Figure 53 MREVCS Pulse Sequence u cscsscsercesesssstsesesenensesoreneesnsonencesesonensenesonsersnenenoes 110 Figure 54 MQ SOLIDS Pulse Sequence oo cece eeeecsesceseeseeeesecseseeeeeseceeeseeseeaecaeeaeeaeaeeeeeeeas 111 Figure 55 SPINDIFF Pulse Sequence sescsercenercsorsenerssstsensssssenensssosenensesosenensenerenensenes 111 Figure 56 FASTACQ Pulse Sequence NEEN 113 Figure 7 NUTATE Pulse Sequence ENNER REENEN Ee EENEG 113 List of Tables Table 1 Background Nuclei of Rotor Material cc eeeeceecsseceseceeeeceeceseeeeeeesecseeseeeeenesaeeseeaeeaees 20 Table 2 Typical Spin Rates with Associated Bearing and Drive Values 0 cseeesseseeeeseeeeeeees 22 Table 3 Reference Materials and IC Chemical Shifts ccc sssssssssssessssseessssseesssseesssseeessssseessssees 34 Table 4 Bessel Filter Outputs EEN 37 Table 5 Wideline Experiment Commands and Parameters 00 0 0 ee eseese cece cee ceseeeceseeeeneeeeees 41 Table 6 Rotor Synchronization Controls AEN 55 Table 7 Rotor Controller Gain Setting and Typical Ranges oo eee eeeeee esse ce ceseeseceseeeeeneeeeeens 57 Table 8 Multiacquisition Quadrature Corrections for MREV8 A 102 Table 9 Multiacquisition Quadrature Corrections for BR24 seesseseesesseeseseeeeeereisrrersrsreree
78. eceeeaeceaeseeceeeeseceeeeseeseeeeeeeeseas MASEXCH1 Pulse Sequence cscccscssssssscsesesecsessecssseseesesessescassersersnesesesorsocerseesess SPOS MOD PullSe Sequence siccssesiesssescscsasseesisesssceeseeesdevwaevesesessasvenstannensnesnsaeneass VACP E EE XPOLDIT 1 Pulse Sequence oo eee ee eeeeeceeseeceecaeecaecsaesaecsaesaececesecneseseseeeeeeeeeteas SQMAS 1 Pulse Sequence sc c 3siseicaeeisceiecseidses scecbs ed lebepesads tisesceadecaetcecetsggebous nesses PASSI EE CPCS Pulse Sequence iieiea a E E a Eaa EEEE iai CPCOSYPS Pulse SCQUEDCE ssisirresierarrensirercirersrises eresse Ee EEn OERE EEEE EN EEEE CPNOESYPS Pulse Sequence ccsisscsscccesssssasccessseuaeseassseisessatevecsnnsnevassenbecscabtontnssnedesuuns RASELPULST E UE DIPSHFTI e SEDRA2 Pulse Sequence sinureni iuen eege 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR List of Figures Figure 41 REDORI Pulse Sequence EEN 91 Figure 42 DOUBLECP1 Pulse Sequence EE 94 Figure 43 TCP Pulse Sequence ENEE iiss abe sie eis a a a aae E Ea EEE e NiE e 95 Figure 44 HAHNCP1 Pulse Sequence EE 96 Figure 45 SSECHO1 Pulse Sequence seccsercesercestseresesetsesosessenesonsesesenensetenenenserensnneneres 98 Figure 46 WLEXCHI1 Pulse Sequence ENEE 100 Figure 47 FLIPFLOP Pulse Sequence ENEE 104 Figure 48 HS90 Pulse Sequence suisia aeisi ibose tea r EE ees EE aS 105 Figure 49 MREV8 Pulse Sequence EEN 106 Figure 50 BR24 Pulse Sequence 2 2 2 cccscteesseseesc
79. ected in 37 milliseconds of which 20 milliseconds is the acquisition time of the two FIDs By adding a loop statement and setting the value if nf number of FIDs is greater than one a series of alternating multinuclear FIDs can be collected Figure 55 is a diagram of the fast acquisition pulse sequence called FASTACQ Figure 55 FASTACQ Pulse Sequence Macro 0 0u 1 0u 0 0u 1 0u 16 0m 16 0m 2 0m 0 0u 0 0u 138 4u 2 0m 0 0u 0 0u 138 4u 2 0e 3 di pi d2 pw 2 0e 3 di pi d2 pw 1 0 beta fb 1 0 beta fb A B A B C The macro fastacq recalls the FASTACQ sequence and a modified parameter set Parameters nf is the number of FIDs to be collected tof is the offset in Hz to be used for the low frequency nucleus freqout is the difference in MHz between the high frequency nucleus defined by tn and the low frequency nucleus 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NVR 110 Chapter 6 Solid State NMR Experiments Processing and Display Data is processed by the command wft n This allows the data to be transformed in the form of an arrayed experiment All the data can be displayed with the dssh command Portions of the data can be displayed with the standard arguments of the command dssh 6 37 NUTATE Solids 2D Nutation 111 NUTATE is a two dimensional solids nutation experiment patterned after that of Lippmaa and coworkers The experiment illustrates the effect of pulse widt
80. ed for the bias to come on fully and thus for the amplifier to provide full output power Allowance for this delay must be made in any pulse sequence programming using rofl The amplifier can be driven in either of two modes e Continuous wave CW the maximum power output is limited to 200 W but the duty cycle can be 100 e Pulsed the maximum power output is 1 kW but the maximum pulse width is 8 ms with a maximum duty cycle of 10 The amplifier is fully protected against thermal overload excessive duty cycle and excessive pulse width Status lights on the front panel and switches for this unit are visible by opening the front door of the third cabinet 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 36 Chapter 3 Wideline Solids Module Operation 37 Although you should study the AR manual before using the amplifier an abbreviated set of operating instructions are given here words in all capital letters refer to controls on the front panel The gating input to the amplifier is of positive logic with a 5 V on and 0 V off signal The amplifier is class A with noise blanking in the CW mode In the pulsed mode the amplifier operates class AB and the gating input acts as a gating signal When gated off the output is greatly attenuated e To operate in the continuous mode turn on the POWER button wait for the STANDBY button to light then press the OPERATE button In the continuous mode the gating signal input should
81. ed magnitude of the quadrupolar coupling is dependent on orientation in the magnetic field and is responsible for the apparent difference between single crystal and powder spectra The most commonly observed quadrupolar nucleus for wideline work is H along with 23Na and a few other nuclei Line shape is of prime consideration in most experiments involving these nuclei Relaxation measurements are also of interest To measure an accurate representation of the line shape most spectra are measured with an echo sequence first described by Mansfield commonly known as the solid echo or quadrupolar echo sequence To simplify phasing of the transformed FID the echo is Fourier transformed from the top of the echo onwards in time and these echoes are usually oversampled For quadrupolar nuclei I gt 3 2 because different types of line shape information may be sought a number of different echo sequences may be used depending on the quantum transitions in interest Figure 44 is a diagram of the SSECHO1 pulse sequence p180 p1 pw d1 d2 tau1 tau2 N at Figure 44 SSECHO1 Pulse Sequence Applicability SSECHO1 is available only on YN YINOVA and UNITYplus It is found in userlib Macro The macro ssechol converts a parameter set for the quadrupole echo pulse sequence SSECHO1 Power parameters and pw are retained If tpwrm is not present as in many VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800
82. eference 13 User Programming 13 VT pneumatics tachometer box 50 W WAHUHA pulse sequence 98 warnings defined 8 waveform generator 71 waveforms 72 creating custom 73 wft command 111 117 VNMR 6 1C User Guide Solid State NMR WHH 4 pulse sequence 98 wideline analog to digital conversion ADC board 34 experiments 59 module hardware 34 NMR experiments 38 patterns 70 Wideline Receiver and Filter board 35 wim parameter 70 WIM 24 cycles 70 windows intervals 98 wisel macro 71 WISE pulse sequence 70 wlexch1 parameter 97 WLEXCH1 pulse sequence 97 X X channel modulation 72 xgate statement 45 xmodcos macro 73 xmodramp macro 73 xnoesysync macro 67 XNOESYSYNC pulse sequence 67 xpol parameter 59 62 64 82 83 94 xpolar macro 62 XPOLAR pulse sequence 26 30 59 62 xpolarl macro 64 XPOLAR pulse sequence 63 64 xpoledit macro 76 XPOLEDIT1 pulse sequence 76 xpolhmod macro 73 XPOLHMOD1 pulse sequence 72 xpolwfg1 macro 72 XPOLWFGI pulse sequence 71 xpolxmod1 macro 73 XPOLXMOD1 pulse sequence 72 xpwxcal macro 66 90 XPWXCAL pulse sequence 65 Z zirconia rotors 18 20 21 52 01 999162 00 A0800
83. elium or nitrogen contact with any part of the body In contact with the body helium and nitrogen can cause an injury similar to a burn Never place your head over the helium and nitrogen exit tubes on top of the magnet If helium or nitrogen contacts the body seek immediate medical attention especially if the skin is blistered or the eyes are affected WARNING Do not look down the upper barrel Unless the probe is removed from the magnet never look down the upper barrel You could be injured by the sample tube as it ejects pneumatically from the probe WARNING Do not exceed the boiling or freezing point of a sample during variable temperature experiments A sample tube subjected to a change in temperature can build up excessive pressure which can break the sample tube glass and cause injury by flying glass and toxic materials To avoid this hazard establish the freezing and boiling point of a sample before doing a variable temperature experiment 9 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 SAFETY PRECAUTIONS Warning Notices continued WARNING Support the magnet and prevent it from tipping over The magnet dewar has a high center of gravity and could tip over in an earthquake or after being struck by a large object injuring personnel and causing sudden dangerous release of nitrogen and helium gasses from the dewar Therefore the magnet must be supported by at least one of two methods with ropes suspended
84. esonance is a useful approach to this goal Figure 40 is a diagram of the pulse sequence DIr DI lt if rdflag y gt Dec2 n 1 srate I I cntct 2 pw tpwrm Tx E SS V cycles 1 times pw cntct dipolr crossp d1 Dec Pp A Cc Figure 40 REDOR1 Pulse Sequence The REDOR experiment provides internuclear distance data between a pair of heteronuclei often 13C and 5N by means of their mutual dipolar interaction REDOR is a high resolution solids experiment and is therefore performed with magic angle spinning MAS and usually proton cross polarization CP The heteronuclear dipolar interaction is partially averaged by MAS Multiple 13C and 15N pulses synchronized with the MAS rotor speed reintroduce dipolar information into the spectrum as a variation of spectral intensity with time Because REDOR is often performed with cross polarization and proton decoupling it is a triple resonance experiment requiring a three channel spectrometer and a triple resonance probe VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 20 REDOR1 Rotational Echo Double Resonance After initial cross polarization a variable number of 7 pulses are applied to the 3c channel each synchronized with the end of successive rotor periods with acquisition beginning at the following rotor period At the middle of each rotor period 7 pulses are applied to the SN cha
85. f these parameters pwx is the observe 90 pulse length pwx follows the contact time and when set to 90 rotates the observe magnetization to the minus z axis and nulls the NMR signal Array pwx between the 0 and 360 pulse The first null is the observe 90 pulse The signal is negative for 180 null for 270 and positive for 360 When the Hartmann Hahn condition is matched for a non spinning sample the proton 90 pulse pw equals pwx In the presence of spinning a match that causes maximum spectral intensity will be offset in power above or below the true Hartmann Hahn condition If observe pulses are used explicitly in a sequence TOSS REDOR1 HETCORCP1 etc pwx must be measured separately and it is usually present as a separate parameter For HETCORCPI1 pwx must be set to pw by adjusting t pwrm and pw is used for both observe and proton pulses phase 2 sets the phase of pwx 90 to the contact pulse and is necessary for measurement of pwx Setting phase 1 sets the two phases the same and all array members of a pwx array have the same intensity 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 66 Chapter 6 Solid State NMR Experiments 6 4 XNOESYSYNC Rotor Sync Solids Sequence for Exchange 67 The XNOESYSYNC sequence is the CP MAS equivalent of a NOESY but with the first 90 pulse replaced with cross polarization Unlike normal NOESY the mixing time can be rotor synchronized In the solid state e
86. f delaying until the next dark to light rotor edge This is mode 2 in Figure 18 The Acquisition Controller board or Pulse Sequence Controller board can be instructed to delay precisely n rotor periods This is done by interrupting an internal counter that is normally reset at each rotor edge delaying n edges and then counting the counter down to zero At this point the delay is finished Thus in principle the error in the delay will be only that percentage that the first and the last periods differ This is shown as mode 3 in Figure 18 Trigger on 2nd edge Delay 5 periods q lt mode 2 mode 3 Rotor period p Start of event end of event mode 1 Figure 18 Different Modes of the Rotor Synchronization Accessory A potential source of error exists in determining the point of the light transition on which to trigger the digital circuitry This is a factor determined by two variables the light detection circuitry and the markings on the rotor VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 5 2 Rotor Synchronization Operation For light detection the tachometer box provides the light source and the detector The rotor has a blackened sector on its base Figure 19 so that as it rotates differing amounts of light are reflected The light is transferred through light pipe to the stator base The reflected light is sampled by another light pipe and brought back to the tachometer box where it is photode
87. f the gas supplies to the probe is altered in the following ways e Body cooling gas is also needed whenever the probe is not at ambient temperature Connect the VT gas supply to the probes is made as described in the Doty manual e The VT controller is connected to the boost supply and the boost supply is connected to the probe e The liquids upper barrel is pushed down so it touches the top of the probe The upper barrel then acts as an exhaust stack VT operation requires Vespel end caps Vespel is less susceptible to thermal deformation at high temperatures and has a lower coefficient of expansion so is less likely to slip out at low temperatures Changes in temperature should always be kept small because rapid changes can cause rotor crashing VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Chapter 6 SOlid State NMR Experiments Sections in this chapter 6 1 XPOLAR Cross Polarization UNITY page 59 6 2 XPOLAR1 Cross Polarization UNITYINOVA amp UNITYplus page 63 6 3 XPWXCAL Observe Pulse Calibration with Cross Polarization page 65 6 4 XNOES YS YNC Rotor Sync Solids Sequence for Exchange page 67 6 5 MASEXCH1 Phase Sensitive Rotor Sync Sequence for Exchange page 68 6 6 HETCORCP1 Solid State HETCOR page 69 6 7 WISE1 Two Dimensional Proton Wideline Separation page 70 6 8 XPOLWFG1 Cross Polarization with Programmed Decoupling page 71 6 9 XPOLXMO
88. fier is class AB capable of delivering 100 W for up to 250 ms Power Control Box 200 MHz and 300 MHz Systems Only A free standing power control box with an ON OFF switch activates the 100 W decoupler and observe amplifiers class C only This box should be located in a convenient location near the operator The computer controls the power levels for decoupling Fine Attenuator UNITY only In a basic UNITY system the power levels for observe and decouple transmitters are set by computer controlled attenuators with a 63 dB range in 1 dB steps This is not fine enough control for solids experiments so the decoupler channel is supplemented with a fine attenuator with a 6 dB range in 4096 steps The fine attenuator is controlled by the parameter dpwr f which ranges from 0 least power to 4095 most power VXR S uses the parameter dhp which ranges from 0 to 255 maximum power Decoupler Amplifier The decoupler amplifier is housed in the lower right side of the console This amplifier increases the output of the standard decoupler to about 100 W to provide sufficient power for dipolar decoupling The output goes to the probe through a high pass filter at the DEC connector on the probe The amplifier on the 200 MHz and 300 MHz systems can be left in the decoupler line since when the amplifier is turned off its input and output are connected A safety circuit shuts off the amplifier and sounds a buzzer if the output of the amplifier is
89. for many such experiments In H wideline experiments lineshape or chemical shift is usually of minor importance The most interesting parameters are relaxation rates such as Ty T2 and Tjp In many measurements the relevant part is the first few microseconds of the FID The FID may not even be transformed 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 38 Chapter 3 Wideline Solids Module Operation Normally the breadth of a line comes from two sources dipolar coupling and chemical shift anisotropy There are a number of techniques referred to as line narrowing or multipulse techniques to remove dipolar coupling contributions to lineshape Quadrupolar Nuclei I 1 or 3 2 For all quadrupolar nuclei the main cause of linewidth is the quadrupolar coupling of the nuclei being observed The observed magnitude of the quadrupolar coupling is dependent on orientation in the magnetic field and is responsible for the apparent difference between single crystal and powder spectra The most commonly observed quadrupolar nucleus in wideline is 2H deuterium along with 23Na and a few other nuclei Lineshape is of prime consideration in most experiments involving these nuclei with relaxation measurements also of interest To ensure an accurate representation of the lineshape most spectra are measured via an echo sequence first described by Mansfield Phys Rev 137 A961 1965 commonly known as the solid echo sequence To
90. from the ceiling or with the antivibration legs bolted to the floor Refer to the Installation Planning Manual for details WARNING Do not remove the relief valves on the vent tubes The relief valves prevent air from entering the nitrogen and helium vent tubes Air that enters the magnet contains moisture that can freeze causing blockage of the vent tubes and possibly extensive damage to the magnet It could also cause a sudden dangerous release of nitrogen and helium gases from the dewar Except when transferring nitrogen or helium be certain that the relief valves are secured on the vent tubes WARNING On magnets with removable quench tubes keep the tubes in place except during helium servicing On Varian 200 and 300 MHz 54 mm magnets only the dewar includes removable helium vent tubes If the magnet dewar should quench sudden appearance of gases from the top of the dewar and the vent tubes are not in place the helium gas would be partially vented sideways possibly injuring the skin and eyes of personnel beside the magnet During helium servicing when the tubes must be removed follow carefully the instructions and safety precautions given in the magnet manual Caution Notices Observe the following precautions during installation operation maintenance and repair of the instrument Failure to comply with these cautions or with specific cautions elsewhere in Varian manuals violates safety standards of design manufacture an
91. g pulse width specification to increments to 0 025 us Adjustment of the power with the parameter tpwr will alter the 90 pulse width parameter pw90 In addition the parameter t pwrm can be used with UN TYTNOVA and UNITYplus systems 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 40 Chapter 3 Wideline Solids Module Operation 3 5 Standard Wideline Samples Two standard wideline samples are provided with the system malonic acid d for H and sodium nitrate for 7 Na wideline NMR These samples are provided as an aid to becoming familiar with the operation of the wideline module and do not have any associated specifications 41 Obtaining a Wideline Spectrum of Deuterium The deuterium powder pattern spectrum of malonic acid d4 can be obtained in the following manner this is not the only way to operate the wideline module but does provide a convenient starting point 1 10 11 12 Determine the 90 pulse using a solution in this case 2 DO for most other quadrupolar nuclei a 1 M solution of a salt in water should be used Put the relevant tuning rod into the probe Connect the correct coil in the correct pair of connectors on top of the probe body Refer to the probe installation manual for details on setting up the wideline probe Place a sealed sample of 2 DO in the probe and put the probe into the magnet Connect body air VT gas and the Normal connector on the magnet leg to the probe No filters a
92. g removal 59 interaction 87 nuclei for wideline experiments 38 dipolr parameter 64 65 86 96 dipshift1 macro 86 DIPSHIFT1 pulse sequence 85 display command 109 dm parameter 62 65 67 80 dn2 parameter 90 92 dof2 parameter 90 92 dotflag parameter 43 Doty CP MAS probe 57 rotors 18 20 53 Double Cross experiment 91 doublecp1 macro 92 double resonance experiments 38 dps command 70 86 91 dpwr parameter 64 65 96 dpwr2 parameter 90 92 dpwrf parameter 17 dpwrm parameter 16 96 dpwrm2 parameter 16 90 dpwrm3 parameter 16 drive pressures and flowrates 21 dssh command 111 duty cycle 26 E echo parameter 96 echo sequence 95 113 VNMR 6 1C User Guide Solid State NMR for wideline experiments 39 EHT power supply 44 electric quadrupole 14 end caps for rotors 18 exchange experiment 82 spectroscopy 97 exhaust stack for VT solids 56 external secondary spectral referencing 31 timing event 51 F fast acquisition 110 fastacq macro 110 FASTACQ pulse sequence 110 fb parameter 35 FIDs FLIPFLIP real channel pattern 46 tram tracks 47 field homogeneity adjustment 22 filling solids rotors 18 film materials in a rotor 19 fine attenuator 17 flammable gases warning 9 flipflip macro 101 FLIPFLIP pulse sequence 46 101 flipflop macro 46 102 FLIPFLOP pulse sequence 47 101 flowmeter for solids probe 21 freqout parameter 110 G gain control 52 GammaB 1 values 95 gated
93. g t auc does not have any effect on the experiment mp_at is the true acquisition time based on np and tau mp_at is recalculated each time np or tau is changed Altering mp_at has no effect on the experiment References D P Burum and W K Rhim J Chem Phys 71 944 1979 T M Barbara and L Baltusis J Magn Reson 106 182 1994 6 32 CORY24 Cycled CORY24 Multiple Pulse Line 105 Narrowing CORY 24 is one of several multiple pulse sequences that removes the strong homonuclear dipolar interactions allowing for pure chemical shift spectra to be obtained for Ip and Tip nuclei in the solid state Figure 51 is a diagram of the CORY24 sequence and Figure 50 is a diagram of Cycled CORY24 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 32 CORY24 Cycled CORY24 Multiple Pulse Line Narrowing 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 0 2u i 3 l gt gt SIO SIM aln alo alanla An S Vaol Wl alsia sja Bla ols el e ls fo fs fo x e e x e x o T 1 0s vt vt CH CH CH CH CH CH CH CH D
94. h on the spectra obtained The 2D spectrum places chemical shift along F and yB along F4 Figure 56 is a diagram of the sequence 0 0u 52 0m 1 0s Tx d1 d2 Figure 56 NUTATE Pulse Sequence Macro The macro nutate converts an S2PUL sequence parameter set into a 2D nutation experiment Parameters tpwr should be set so that a 90 pulse length should be about 50 kHz or whatever other value is desired sw1 controls the length of the tip angle using as the increment value 1 sw1 in an analogous way to all standard 2D experiments Processing The data is processed by the command wft2d 0 0 0 1 Reference Samoson A Lippmaa E J Magn Reson 1988 79 255 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Numerics 3QMAS1 pulse sequence 77 6 dB fine attenuator 17 90co phase shift 102 90co pulse determination 101 A absolute position of CP MAS rotor 50 absolute value plot 68 Acquisition Controller board 50 Acquisition Status window 53 adamantane 22 27 ADC conversion time 35 adjust magic angle 23 adjusting homogeneity of sample 22 magic angle 23 air supply 50 for spinning Doty rotors 20 amorphous silicon semiconductors 70 AMT linear amplifier 16 35 37 analyze command 30 61 analyze inp text file 61 angle measuring gauge 23 angled brackets lt or gt notation 12 angular instability in magic angle spinning 25 Applications Laboratory 13 AR linear amplifier
95. he high resolution COSY experiment CPCOSYPS can be run as a direct polarization experiment or the first 90 pulse can be replaced with a cross polarization pulse element Figure 35 is a diagram of the sequence As with COSY correlations are present between resonances that share a J coupling CPCOS YPS is of greatest use when J coupling is large for example 31P in organometallic compounds When J coupling is small use CPNOESYPS which depends on the through space dipolar interaction cntct pwx tpwrm t Tx Ge 7 pw cntct dipolr crossp d1 Dec bn A Cc Figure 35 CPCOSYPS Pulse Sequence Applicability CPCOSYPS found in user1ib is available only on N YINOVA and UNITYplus Macro The macro cpcosyps converts a parameter set obtained with XPOLAR or XPOLARI for the solids homonuclear correlation experiment CPCOSYPS Power levels and the IH VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 16 CPNOESYPS Cross Polarization Phase Sensitive NOESY 90 pulse width are retained Default parameters set up for a phase sensitive hypercomplex acquisition with swl sw and xpol y Parameters cpcosyps uses UN TYINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters xpol is set to n for preparation by direct polarization xpol is set to y for preparation by cross polarizati
96. ib version 2 1 Parameters WISE uses the UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pwand cntct see page 63 for a description of these parameters mixflag y adds two 90 pulses that bracket a mixing period for proton spin diffusion mixflag n provides a proton pulse evolution period and cross polarization References Zumbulyadis N Physical Review B 1986 33 6495 Schmidt Rohr K Clauss J Spiess H W Macromolecules 1992 25 3273 3277 6 8 XPOLWFG1 Cross Polarization with Programmed 71 Decoupling XPOLWFGI1 is a version of XPOLARI that provides for programmed decoupling during acquisition using an optional waveform generator Decoupler patterns are found in DEC files in the directory shapelib In principle any decoupler pattern can be used though it should be noted that most liquids patterns waltz xy 32 etc are not necessarily useful for solids Several useful patterns are described below and are included in the shapelib directory of SolidsLib version 2 1 XPOLWFGI gates the waveform generator on and off with a fastline no AP bus delay at the beginning and end of the acquisition period if dm nny and dmm ccp If dm c the usual continuous wave decoupling is applied and as usual if dm n no decoupling is applied XPOLWFGI does not include p180 toss pdp and pcrho at present Applicability XPOLWFGI is available for UNITYplus and UNTY INOVA systems and can be f
97. idebands While these spinning sidebands contain information about the chemical shift anisotropy they can complicate the interpretation of complex spectra The sidebands can be eliminated using the TOSS TOtal Sideband Suppression technique The TOSS pulse sequence is selected by setting toss y Note that the parameter s rate should be set to the spinning speed in Hz TOSS uses 180 pulses based on the parameter pw It may be necessary to adjust pw to optimize the TOSS experiment Figure 21 shows the pulse sequence diagram for cross polarization with TOSS xpol y toss y level2 pw leveli H ty d1 p2 1 36 Delay recipe including srate Figure 21 TOSS Pulse Sequence Suppression of Protonated Carbons Interrupted Decoupling Off resonance decoupling and related experiments such as DEPT in which J coupling is involved are not usually possible in solids because through space dipolar coupling as well as J coupling is present An experiment exists however that can be used to discriminate between protonated and nonprotonated carbons this is the protonated carbon suppression experiment of Opella and Fry In this experiment the decoupler is turned off before acquisition to dephase the protonated carbons 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 60 Chapter 6 Solid State NMR Experiments 61 The technique is effective for non mobile carbons Mobile carbons l
98. ike methyl groups are typically not suppressed as well The experiment is run by setting pdp y setting srate to the spinning speed and entering appropriate values for the dephasing time d2 in seconds Figure 22 shows the pulse sequence diagram for cross polarization with interrupted decoupling xpol y pdp y pw level1 l level2 A 1 H d j p2 2 pw 13 d2 1 srate c __ 1 srate Figure 22 Protonated Carbon Suppression Sequence Measurement of TTC me Measurements of the spin lattice relaxation time in the rotating frame Tj are possible using the standard XPOLAR pulse sequence The parameter p3 is the spinlock time after cross polarization Typical values for p3 range from 50 to 5000 microseconds Figure 23 is a diagram of the sequence xpol y pw level1 level2 1 H d1 p2 p3 13 c Figure 23 Rotating Frame Spin Lattice Relaxation Measurements Sequence To analyze a T p experiment of the decay time constant enter analyze expfit p3 t2 list The analyze command has four arguments The first argument is expfit The analyze program provides an interface to the curve fitting program expfit supplying it with the input data in the form of a text file analyze inp in the current experiment analyze inp is generated by a line listing of the peaks of interest in a spectrum and by the fp command which measures the peak height of each peak in an array of spect
99. ined Parameters PASS1 makes use of the YN YJNOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters pwx is the observe 90 pulse in microseconds pass is set to y for 2D PASS Set pass n for normal cross polarization sw1 is not used and may be set arbitrarily sw1 16 is recommended nt must be a multiple of 243 a n m is a set of arrays containing the PASS delay values in units of 1 srate These are converted to absolute delays using the value of srate For the current experiment n 6 and m 16 to obtain a manifold of 16 sidebands Other values can be VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 14 CPCS Cross Polarization with Proton Chemical Shift Selection calculated numerically using reference 1 The user might place an import function in the pulse sequence to enter these values automatically from a text file Reference Antzukin O N Shekar S C Levitt M H J Magn Reson 1995 115A 7 6 14 CPCS Cross Polarization with Proton Chemical Shift Selection Figure 34 is a diagram of the CPCS experiment developed by Spiess and coworkers to study component mixing on a molecular scale This novel experiment involves a multiple pulse selection of H magnetization based on chemical shift differences during a mixing time IH spin diffusion during a mixing time and high resolution DC CP MAS detection cntct
100. intensity Typically plots of spectral intensity versus the number of rotor cycles are generated and the internuclear distance can be determined by simulation of the resulting curve A 7 2 pulse placed every 8 cycles cancels the effect of SEDRA and provides a control experiment Applicability SEDRA2 found in user1ib is available only on YN YINOVA and UNITYplus Macro The macro sedra2 converts a parameter set obtained with XPOLAR or XPOLARI for the transverse SEDRA experiment of Guillion and Vega Power levels and the proton 90 pulse width are retained The value of pwx must be calibrated use XPWXCAL VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 19 SEDRA2 Simple Excitation of Dephasing Rotational Echo Amplitudes lt if sedrlflg n gt _ 2 pwx pwx X Y X Y Y X Y X cycles times J n 1 srate J ve Se a ser Sei 4 entct Pa topwrm S at Tx pw cntct dipolr crossp Dec e A Cc Figure 39 SEDRA2 Pulse Sequence Parameters sedra2 uses UN TYINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters pwx is the observe 90 pulse in us It determines the length of 7 pulses of SEDRA cycles is the number of 8 pulse SEDRA cycles before acquisition Each SEDRA cycle has a length of 8 rotor periods and a 7 puls
101. ional sequence is the HS90 sequence 90 x 90 y 90 y 90 x 2 acq which tests the exactness of the 90 phase shift This sequence first described by Haubenreisser and Schnabel is a very accurate measure of phase shift errors The sequence is 8 pulses per acquisition point Figure 47 is a diagram of HS90 A benefit of this sequence is that it is insensitive to B homogeneity Any phase error between x and y is shown as an oscillation in the number of points per cycle is related to the phase error The phase error can be determined by counting the number of points in one cycle of a sine wave Divide 360 by this number The result is the phase error in degrees If the result is less than 0 1 degrees there is no error if the result is greater than 0 1 degrees there may be a fault in the transmitter board The macro hs 90 recalls the sequence and a modified parameter set 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 102 Chapter 6 Solid State NMR Experiments phase 1 phase2 pw acq X y y kK X y k d1 LI np 2 times tau i Figure 47 HS90 Pulse Sequence Parameters pw is the pulse length in microseconds usually set to a 90 pulse phase1 is the phase of the first 90 pulse and is set to 0 x phase2 is the phase of the second 90 pulse and is set to 1 y trigissetto y or n depending on the system On UN YINOVA and UNITYplus the pulse sequence in
102. ipolar etc The multiple pulse FT NMR experiment uses a series of very short 90 pulses and delays that surround windows during which the evolution of the spin system is observed The spin system responds not only to same interactions that occur in the standard NMR experiment but also to the influence of the B pulses and the delays between the observation windows Multiple pulse experiments such as the WAHUHA or WHH 4 sequence developed by Waugh Huber and Haeberlen MREV8 developed independently by Mansfield and by Rhim Elleman and Vaughan and BR24 developed by Burum and Rhim are examples of experiments used to observe the state or condition of the spin systems at intervals called windows Adding the MAS experiment to a multiple pulse experiment further reduces the linewidth Linewidth is reduced with MAS in homonuclear systems in the same way as it is in heteronuclear systems by averaging the chemical shift anisotropy to zero 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 98 Chapter 6 Solid State NMR Experiments 99 Chemical Shift Hamiltonian For any given multiple pulse train the average chemical shift Hamiltonian defined over a complete cycle can be written in the form H sdo n I where dom is the chemical shift offset s is the scaling factor n is a unit vector in the rotating frame and J is the angular momentum vector For the three sequences MREV8 BR24 and CORY 24 n does not lie along the z axis an
103. ird channels and is used only for oscilloscope or dps observation of pulses on a two channel instrument References Guillion T Schaefer J Adv in Magn Reson 1989 13 57 Guillion T Schaefer J J Magn Reson 1989 81 196 Garbow J R McWherter C A J Am Chem Soc 1993 115 238 6 21 DOUBLECP1 Double Cross Polarization Double Cross is the original triple resonance experiment in the solid state Typically the nucleus observed is IN The results are obtained by plotting the difference between the IH ISN cross polarization and the IH to DN to Bc cross polarization spectra for different ISN 13C contact times Figure 41 is a diagram of the pulse sequence lt if dblcpflag y gt cntct2 crossp2 Dec2 cntct tpwrm TX pw cntct dipolr crossp Dec A C B c Figure 41 DOUBLECP1 Pulse Sequence 91 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 22 T1CP1 T Measurement with Cross Polarization Applicability DOUBLECP1 is available only on YN YINOVA and UNITYplus It is found in userlib Macro The macro doublecp1 converts a parameter set obtained by XPOLAR or XPOLARI for the double cross polarization experiment Observe and decoupler power levels and the proton 90 pulse width are retained Third channel power levels and the dilute spin Hartmann Hahn match must be calibrated see crossp2 below Parameters doublecp1 uses the YNITYZ OVA and UNITYplus pa
104. is the repolarization time in microseconds References Sangil R Bildsoe H Jacobsen H J J Magn Reson 1994 107 Series A 67 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 76 Chapter 6 Solid State NMR Experiments 6 12 3QMAS1 Triple Quantum 2D for Quadrupole Nuclei 77 3QMAS1 is a two pulse two dimensional experiment for the detection of isotropic spectra of quadrupole nuclei I n 2 n 2 gt 1 2 in the solid state an optional third selective refocusing pulse may also be present Isotropic spectra of quadrupole nuclei are produced in the f1 dimension The resonance frequencies are determined by both the chemical shift and the quadrupole interaction and are field dependent The lineshape in the f2 dimension is similar to that obtained with MAS alone Because resonances are resolved in f1 the lineshapes are easily simulated individually with a general simulation program such as STARS The shift in f1 and the lineshape in f2 are related and provide redundant information about quadrupole and chemical shift tensor components Figure 32 is a diagram of the 3QMAS1 sequence pw3q pw3q di at tpwrms periods srate A C Figure 32 3QMAS1 Pulse Sequence The pulse sequence and phase cycle are based on work done by D Massiot et al and were first provided by J Stebbins of Stanford University We thank the authors for the opportunity to view their work before publication Applicability 3QMAS1 is availa
105. l provided by the pacemaker manufacturer or contact the pacemaker manufacturer to determine the effect on a specific pacemaker Pacemaker wearers should also always notify their physician and discuss the health risks of being in proximity to magnetic fields Wearers of metal prosthetics and implants should contact their physician to determine if a danger exists Refer to the manuals supplied with the magnet for the size of a typical 5 gauss stray field This gauss level should be checked after the magnet is installed WARNING Keep metal objects outside the 10 gauss perimeter of the magnet The strong magnetic field surrounding the magnet attracts objects containing steel iron or other ferromagnetic materials which includes most ordinary tools electronic equipment compressed gas cylinders steel chairs and steel carts Unless restrained such objects can suddenly fly towards the magnet causing possible personal injury and extensive damage to the probe dewar and superconducting solenoid The greater the mass of the object the more the magnet attracts the object Only nonferromagnetic materials plastics aluminum wood nonmagnetic stainless steel etc should be used in the area around the magnet If an object is stuck to the magnet surface and cannot easily be removed by hand contact Varian service for assistance 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 8 SAFETY PRECAUTIONS Warning Notices continued Refe
106. licon nitride or sapphire with Kel F or Vespel end caps See the manual from the rotor manufacturer for details Varian high speed rotors are composed of zirconia or of silicon nitride SizN4 with PMMA or Torlon type 4203 end caps Refer to the probe installation manual for a list of rotors and end caps and their associated part numbers color temperature range and maximum spin rates During VT operation Torlon end caps can exceed the 100 C specification of the 7 mm probe Below 100 C a potential for slipping due to differential contraction with the ceramic rotor exists Kel F end caps colorless opaque have a VT upper limit of about 70 C and should not be spun faster than 6500 Hz at any temperature pMMA end caps colorless clear must only be used at room temperature and below These are currently supplied with Varian RT CP MAS probes Visually distinguishing between Kel F and pMMaA end caps can be difficult so you may want to mark them appropriately The background nuclei for these materials are listed in Table 1 Table 1 Background Nuclei of Rotor Material Material Background Kel F end cap C not cross polarizable F Vespel Torlon pMMA end cap C cross polarizable H sapphire rotor Al O zirconia rotor Zr O traces of Mg Y Al SN rotor Si N some Al CAUTION Spinning a rotor for more than a few minutes in a vibrating state can cause permanent damage to the bearing surface of both the rotor and stator O
107. lifier Pneumatics tachometer box Wideband receiver Sync module Two fine attenuators For operation of the complete solids module refer to the operations sections in the chapters 2 to 4 for the CP MAS wideline and CRAMPS multipulse modules A wide variety of solids probes and probe accessories are available including wideline multipulse and magic angle probes Optional solids accessories include rotor synchronization rotor speed controller and the solids variable temperature accessory Chapter 5 covers using these accessories VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Chapter 2 CP MAS Solids Operation Sections in this chapter e 2 1 CP MAS Solids Modules this page e 2 2 Preparing the Sample and Rotor page 18 e 2 3 Spinning the Sample page 20 e 2 4 Adjusting Homogeneity page 22 e 2 5 Adjusting the Magic Angle page 22 e 2 6 XPOLAR Pulse Sequence page 26 e 2 7 Calibrating Pulse Width page 26 e 2 8 Calibrating Decoupler Power page 26 e 2 9 Adjusting the Hartmann Hahn Match page 27 e 2 10 Optimizing Parameters and Special Experiments page 27 e 2 11 Spectral Referencing page 31 e 2 12 Further Reading on Solid State NMR page 32 e 2 13 Useful Conversions page 33 2 1 CP MAS Solids Modules CP MAS hardware differs between systems CP MAS Hardware for INOVA and UNITYplus systems On UNTYTINOVA and UNITYplus systems
108. lights on the front panel and the power switch are visible inside the front door of the third cabinet as well as on the status panel The gating input to the amplifier is of positive logic with a 5 V on and 0 V off signal CAUTION Never operate a high power amplifier unless terminated by an appropriate 50 ohm load Decoupler Amplifier The three possibilities for the decoupler amplifier in wideline systems are as follows e Standard decoupling operation e 100 W CP MAS decoupler operation of this is the same as for CP MAS e 1 kW decoupler amplifier Status Panel The high power amplifiers are controlled by a status panel The HI POWER ENABLE subpanel contains two switches VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 3 2 Wideline Experiments e The OFF button grounds the inputs of both high power amplifiers and routes the transmitters through the standard YN YINOVA UNITYplus and UNITY electronics appropriate for liquids operation note that both amplifiers are left powered up by this switch e If HI POWER ENABLE is OFF the position of the HI POWER LO POWER switch is immaterial the high power amplifiers cannot receive any rf drive The ON switch activates the cabinet enabling the HI POWER LO POWER toggle switches Observe Transmitter For both the solids and standard liquids channels the computer controlled attenuators are in line The power level is controlled by the parameter t pwr in 1 dB increments from
109. microseconds mix is the mixing time in microseconds for spin diffusion ni is the number of increments as defined in standard 2D NMR usage ni s is typically set to either 64 or 128 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 36 FASTACQ Multinuclear Fast Acquisition Tx Reference 6 36 FASTACQ Multinuclear Fast Acquisition Zheng L Fishbein K W Griffin R G Herzfeld J J Am Chem Soc 1993 115 6254 Fast acquisition of data has interesting applications particularly in high temperature fast kinetic studies Of particular interest is the ability to perform fast acquisitions in the following manner to do in double resonance X Y the fastest possible acquisition of sequential spectra of two nuclei for example pulse acquire 27Al pulse acquire 2H pulse acquire 27Al storing FIDs in separate buffers The particular example used here is the simultaneous observation of 27 A and 7H For this experiment a triple resonance probe was used with the coil doubly tuned to 27A referred to as the high frequency and 7H referred to as the low frequency Both NMR frequencies were picked off the high frequency port It was possible to observe the 2H signal due to the imperfect isolation between the two channels By coding a pulse sequence using the offset pulse sequence statement in conjunction with large values of tof in MHz two FIDs one at 21 Al and the other at 2H were coll
110. mple must be greater than the CSA in order to reduce the resonance to a single narrow approximately 1 ppm line at the isotropic frequency If the spinning speed is less than the CSA a pattern of sidebands occurs about the isotropic peak at integral values of the spinning frequency The CSA scales linearly with Bo A third source of line broadening in solids occurs when observing nuclei that possess an electric quadrupole The quadrupolar interaction can be as large as several MHz For nonintegral spin quadrupolar nuclei the central transition is much narrower about 10 kHz and therefore can be narrowed to a single narrow line by magic angle spinning The residual second order linewidth of the central transition is inversely proportional to the applied magnetic field 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 14 Chapter 1 Overview of Solid State NMR 1 2 Spin Lattice Relaxation Time An additional characteristic of some nuclei in the solid state for example BC is a long spin lattice relaxation time T1 To overcome this problem the abundant nuclei usually protons in the system are used These are polarized with a spin locking pulse CP The polarization is then transferred to the rare spins by applying an rf field at the Larmor frequency of the rare spins that is of such a magnitude as to make the energy levels of the abundant and rare spins the same in the rotating frame Hartmann Hahn match condition Following a t
111. mplements either a quadrupole echo or a composite echo see compul below echo set to n implements a single pulse the first pulse of the quadrupole echo with width pw The delay before acquisition is taul tau2 tpw A difference spectrum n y selects a quadrupole echo spectrum in the presence of a large central resonance compul set to y implements a composite pulse echo 135 x 90 x 45 x instead of a quadrupole echo if echo y p1 is the width of the first pulse of the quadrupole echo in microseconds set to 90 or if set to zero p1 pw When p1 is 0 it is hidden pw is the width of the second pulse of the quadrupole echo in microseconds set to 90 if spin I 1 or set less than 90 if spin I is greater than or equal to 3 2 I is the nuclear spin quantum number p180 is an optional inversion pulse in microseconds for T studies If p180 is 0 this parameter is hidden see d2 below d2 is the delay in seconds between the inversion pulse and the quadrupole echo if p180 is 0 d2 is not used and is hidden taul is the delay in microseconds between pulses p1 and pw of the quadrupole echo pulse sequence tau2 is the exact see NOTE below delay in microseconds between the second pulse and acquisition Set tau2 less than tau1 to begin acquisition before the top of the echo Use 1sfid greater than 1 to begin the Fourier transform at the echo peak see below NOTE The delay to compensate for filter group delay
112. ms or page 63 UNTYTNOVA and UNITYplus 2 7 Calibrating Pulse Width The steps below provide instructions for calibrating the pulse width as well as for connecting the amplifiers and setting the parameters CAUTION To avoid severe damage to the probe make sure that the values for the parameters level1 and level2 do not exceed the values given for maximum power for the probe 1 Insert a rotor containing p dioxane and spin it at about 200 Hz 2 Record a spectrum using gated decoupling dm nny and calibrate the 90 flip time 3 Recall the parameters from parlib xpolar and set d1i 5 nt 1 xpol n tpwr 45 tpwrf 4095 Vary pw If needed you can create tpwrf with the following commands create tpwrf integer setlimit tpwrf 4095 0 1 Depending on the probe 90 pulse widths can range anywhere from 4 0 to 9 0 us The observe transmitters can deliver up to 300 W for up to 20 ms except on VXR S Develop a matrix of tpwr and tpwrf values as they relate to pw90 and save the matrix for later reference CAUTION Do not use more than 5 duty cycle for a pulse longer than 0 2 second for the decoupler For the standard XPOLAR pulse sequence an error message displays when the duty cycle reaches 20 Refer to individual probe data sheet for maximum pulse duration 2 8 Calibrating Decoupler Power Using the previously determined pw calibrate decoupler power yB gt as follows 1 Recall test parameters by entering rt vnmr
113. n ft ft inverse n expn jexpn scalesw 1 0 n df wft In this example n in the ft command is a interpolation factor power of 2 expn is an experiment number for the interpolated FID df interpolates the FID by a factor of n and the echo top may be picked more accurately scalesw 1 0 n will correct sw It is also common to collect wideline spectra with the transmitter placed in the exact center of the resonance Software is provided to allow phasing the FID to place as much as possible of the FID in the real channel This operation means that the frequency independent phase shift of the spectrum is as close to zero as possible which is beneficial since frequency domain phasing of wideline spectra can be difficult at best In addition spectral symmetry can be forced by software that sets the imaginary channel of the FID to Zero VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Chapter 4 CRAMPS Multipulse Module Operation Sections in this chapter e 4 1 CRAMPS Multipulse Module Hardware this page e 4 2 Running the FLIPFLIP Pulse Sequence page 46 e 4 3 Running the FLIPFLOP Pulse Sequence page 47 e 4 4 Using MREV8 to Demonstrate Multipulse Operation page 48 The CRAMPS multipulse module is available for 300 MHz and 400 MHz spectrometer systems It provides wideline capability for H and 9F including the ability to perform multipulse experiments such as MREV8 and BR24 The standard li
114. name Set dmf and dres according to the text in each shapefile tppm2 DEC provides phase modulated decoupling as presented by Bennett et al For crystalline materials for example glycine and linear polyethylene PM decoupling narrows the residual linewidth up to about 30 over CW decoupling The pattern consists of approximate 7 pulses with alternating phases of about 10 to 30 degrees Vary dmf and the phase angle in the DEC file for best decoupling at a particular field strength and spinning speed blew 48 DEC provides decoupling with BLEW 48 according to Burum et al BLEW 48 decouples protons from themselves but leaves a scaled Wetz dipolar interaction fslg2 DEC provides phase continuous frequency switched Lee Goldberg decoupling This pattern decouples protons from themselves but leaves a residual Dely dipolar interaction Reference Bennett A E Rienstra C M Auger M Lakshmi K V Griffin R G Poster 368 36th Experimental Nuclear Magnetic Resonance Conference 1995 6 9 XPOLXMOD1 Waveform Modulated Cross Polarization XPOLXMOD provides modulation of the X channel of the Hartmann Hahn match with a selected waveform file A second sequence XPOLHMOD1 modulates the proton channel In general modulated CP improves signal to noise and quantitation of CP MAS spectra at 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NMR 72 Chapter 6 Solid State NMR Experiments 73 Dec high spinni
115. nce this happens the rotor will probably not spin adequately again even if perfectly balanced 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 18 Chapter 2 CP MAS Solids Operation 19 Homogeneous Machinable Solids Although some hard machinable polymers can be made directly into solid rotors it is much easier to make a plug for the standard hollow rotor The signal to noise difference is not that significant The fit must be tight enough to prevent the plug from rattling around or slipping out during spinning The sample material must be homogeneous and free of voids for the spinning rotor to remain balanced One way to remove a sample plug is to drill and tap a center hole about halfway through the plug for a 2 56 screw This is best done on a lathe to facilitate centering and ensure balance A small screw is then used to extract the plug For Varian 7 mm rotors the solid sample should be machined as a plug to fit into the rotor Ideal dimensions should be 0 440 0 005 in 11 176 mm long by 0 1960 0 0005 in 4 979 mm in diameter 0 137 in 3 48 mm for Varian 5 mm rotors Granular and Powdered Materials For granular or powder materials the best method for filling the rotors is by pouring the material into the rotor leaving just enough room for the cap Granular and powdered materials work best as uniform fine particles 100 mesh or finer If the material can be ground it is better to do so before attempting to p
116. ng speeds These two sequences provide access to a variety of the phase frequency and amplitude modulated CP methods in the literature Two macros xmodcos and xmodramp create specific amplitude modulated cosine and ramped waveform DEC files This sequence requires a waveform generator on the appropriate channel X or H Without a waveform generator or for general purposes use VACP instead Figure 29 is a diagram of the sequence entct tpwrm Tx xpolxmod1 pattern at pw xpolhmod1 pwpuls entct crossp xpolhmod1 pattern A C Figure 29 XPOLXMOD Pulse Sequence Applicability XPOLXMOD 1 and XPOLHMOD are available on UNITYplus and UN TY INOVA and present in userlib One waveform generator is required and it can be placed on channel 1 or channel 2 as needed Macros The macros xpolxmod1 and xpolhmod1 convert a parameter set obtained with XPOLAR or XPOLAR for these experiments Power levels and pulse widths are retained For VNMR 5 1 and later crossp scales the proton waveform and tpwrm scales the X waveform The macros xmodramp and xmodcos create their respective DEC files They also serve as a prototype for the creation of custom waveforms Parameters XPOLXMOD1 and XPOLHMOD I make use of the UNITYplus and YNY INOVA parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pn and center See page 63 for a description of these parameters All other functions i e toss etc of XPOLAR
117. ngs a video card PC monitor and keyboard will have to be attached so that the CMOS set up program not part of DOS can be run 5 4 Variable Temperature Operation with Solids This section provides general instructions on the solids variable temperature VT accessory The accessory installation manual for the system provides more detailed instructions on solids VT Varian Solids VT System The Varian solids variable temperature accessory Part No 00 958994 00 can be added to a Varian VT CP MAS probe for VT operation When this accessory is added connection of the gas supplies to the probe is altered in the following ways e Body nitrogen is needed whenever the probe is in operation The connection of the VT gas supply is described in the VT installation manual e The VT controller is connected to a booster power supply and the booster power supply is connected to the probe This is accomplished with the solids VT cable as described in the VT installation manual e The liquids upper barrel is pushed down so it touches the top of the probe This together with the Varian bore vent assembly serves as the exhaust stack e VT operation requires the use of Torlon end caps 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 56 Chapter 5 Solid State NMR Accessories 57 Doty Solids VT System The Varian solids VT accessory can also be added to the Doty CP MAS probe for VT operation When this accessory is added connection o
118. nnel These IN pulses cause signal loss due to the dipolar interaction A spectrum without DN pulses serves as a control experiment The typical plot is So S S where S is the spectral intensity the and ISN pulses and So is the intensity without The carbon nitrogen bond distance is determined by simulation of the curve Applicability REDOR is available only on UN TYINOVA and UNITYplus systems Macro The macro redor1 converts a parameter set obtained with XPOLAR or XPOLARI1 for the REDOR experiment with xy8 7 pulses on the observe channel Observe and decoupler power levels and the proton 90 pulse width are retained Third channel power levels and pulse width must be calibrated see p1 below Default parameters yield an array of spectra for 2 to 32 rotor cycles Alternate spectra are obtained without and with third channel 7 pulses For best results adjust tof and dof2 see dof2 below so that the peak of interest is on resonance Parameters redor1 uses Y YINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters rdflag is set to y to apply 7 pulses to both the observe and third channel and thus obtain REDOR modulation of the peak intensity rdflag is set to n to apply 7 pulses only to the observe channel and thus obtain observe peak intensity without REDOR modulation Typically the array rdflag n y is used cycles is the number of
119. not connected to 50 ohms If this happens the ON OFF switch on the amplifier must be turned to off the fault rectified and then the switch turned back to on The amplifier on the 400 MHz system has a separate power switch instead of the control box and when the amplifier is turned off the input and output are not connected Included on this amplifier is dynamic overload protection VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 2 Preparing the Sample and Rotor The decouple amplifier is driven by the normal liquids decoupler output which can be as high as 50 W at maximum output This is more than sufficient to drive the decoupler amplifier and if used at full power can damage the decoupler Although the parameter level2 has been set to 63 in this manual do not use values higher than those that deliver 25 W 200 and 300 MHz systems or 10 W 400 MHz system to the input of the decoupler amplifier 2 2 Preparing the Sample and Rotor Solid samples are normally packed into hollow rotors These rotors are sealed with fluted caps that are driven for spinning The method of filling the rotors depends somewhat on the form and nature of the sample The most critical factor in spinning reliability is the dynamic balance of the filled rotor Some specific recommendations on filling the rotors and achieving a reasonable balance for different kinds of samples are given below Rotor Composition Doty rotors are either of zirconia si
120. not tied to any internal triggering mechanism and t rig should always be set to n On UNITY and VXR data acquisition is triggered to an internal 500 kHz clock so trig must be set to y and the signal of the 500 kHz clock plugged into the external trigger input located on the Pulse Sequence Controller board np is usually set to 128 points tau is 20 microseconds Reference Haubenreisser U Schnabel B J Magn Reson 1979 35 175 6 30 MREV8 Cycled MREV8 Multiple Pulse Line 103 Narrowing MREVS8 is one of several multiple pulse sequences that remove strong homonuclear dipolar interactions allowing for pure chemical shift spectra to be obtained for 1H and ft nuclei in the solid state Figure 48 is a diagram of the MREV8 sequence Macros The macro mrev8 converts a FLIPFLOP BR24 or S2PUL parameter set into the MREV8 line narrowing pulse sequence The macro cylmrev converts the MREV8 parameter set to that suitable to run Cycled MREVS8 No parameter changes are necessary The preparation pulse is based on the value of pw as listed in Table 8 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 31 6 31 BR24 Cycled BR24 Multiple Pulse Line Narrowing prep TI pw acq 0 3 1 2 2 B 0 1 d1 8 L np 2 times fai tant 4 Figure 48 MREV8 Pulse Sequence Parameters pw is the 90 pulse length in microseconds tau is the interpulse
121. nseeeees 18 2 1 CP MAS Solids Modules denke SEENEN ENEE acini alae alien 18 2 2 Preparing the Sample and Rotor 0 eee ceeseceeceeeceeceseeeceseeeeseeeeeeseaeeeeeeaeeeeeenee 20 2 3 Spinning the Sample EE 22 24 Adjusting Homogeneity sn celcssesecescts ccsscsescuceschstesucuschevooducas tivscesseabsesntsxnees E 24 25 Adjusting the Magic Angle sissantina uE E EE E EAE ASi 24 2 6 XPOLAR Pulse Sequence sieisen e aei esei eti EE EE asas 28 27 Calibrating Pulse Width jocssciecdecsnccsccs ccs sseascssoccascsdssvenzsctucgesegisdsseosstscecsevssnsegesscasetorseesses 28 2 8 Calibrating Decoupler Power 0 0 cee ececseseecseesseceeceaeceecaeesecseeseseeeeeseaeteaeeaeeeaeenee 28 2 9 Adjusting the Hartmann Hahn March AAA 29 2 10 Optimizing Parameters and Special Experiment 0 00 00 c ee eeeeeeeeeseeseecseesaeeeeaes 29 201 Spectral Referencing d EERSTEN 33 2 12 Further Reading on Solid State NMR uo eee eee eeeeeeeeeeeseecaeeseecaeceaecaesaeeeeeseeeeee 34 213 Usetul Conversions E 35 Chapter 3 Wideline Solids Module Operation ccccsesseseseeeeseeeenee 36 Sol Widelane Solids MOUs 0s2 c cseseciseccssscvsssecsigcssssosaxseteseusips nekoe ao E AEE REEE 36 3 2 Wideline EXperwments cc sicesciccsSecessescssvsessceezasscsanthvacsyasshbants r EIEI ERTE EEEE oE EERE EEE 40 3 3 SSECHO Pulse Sequence tege ENEE EES Ee 41 BA Data ACqUisitjoN EE 42 3 5 Standard Wideline Samples A 43 3O Data TT 45 Chapter 4 CRAMPS Multipulse Module Operation nsnn
122. nsion Set daslp lt 0 0 for I 3 2 and daslp gt 0 0 for I 5 2 das1p is available for VNMR version 5 2 and later refer to the VNMR Command and Parameter Reference phase 1 2 are the sine and cosine components of hypercomplex Fourier transform wft2da References Frydman L Harwood J S J Am Chem Soc 1995 117 5367 Medek A Harwood J S Frydman L J Am Chem Soc 1995 117 12779 12787 Baltsberger J H Xu Z Stebbins J F Wang S H Pines A J Am Chem Soc 1996 Massiot D Touzo B Trumeau D Coutures J P Virlet J Florian P Grandinetti P J Poster 37th ENC and Solid State NMR 1996 6 73 84 6 13 PASS1 2D Sideband Separation for CP MAS The PASS1 experiment produces a 2D plot with an isotropic spectrum in f1 and a MAS sideband pattern in f2 There is negligible loss of signal intensity Chemical shift tensor components can be determined from the sideband intensities in f2 Figure 33 is a diagram of the PASS1 sequence 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 78 Chapter 6 Solid State NMR Experiments 79 2 pwx 2 pwx 2 pwx 2 pwx 2 pwx entct ae at pw cntct dipolr fm A C Figure 33 PASS1 Pulse Sequence Applicability PASS1 is available on YNTYZ OVA and UNITYplus and present in userlib Macro The macro pass1 converts a parameter set obtained with XPOLAR or XS POL ART for the 2D PASS experiment Power levels and pulse widths are reta
123. nsnnsnnsnnnnnnnnnnnnnnnnnnne 46 4 1 CRAMPS Multipulse Module Hardware seseseeeeeeseeeeseseesrseesereeserreserrssreresreerereesee 46 4 2 Running the FLIPFLIP Pulse Sequence oo eee cece cseceseceeceseeeeeeeeeeeeeeeeeeeaeeees 48 4 3 Running the FLIPFLOP Pulse Sequence 00 0 eee eeeeeceecesecneceseeeeeeeeeseeeeeeeeeaeeees 49 4 4 Using MREV8 to Demonstrate Multipulse Operation 0 0 eee eeseeeeceeeeeeeeeeeees 50 Chapter 5 Solid State NMR Accessories cccseesestenestessceessteeseeeeenenes 52 5 1 Pneumatics Tachometer BOX csscsiccasesiecscesestansssesospeaevonvssdiseosteeieastasiesapesbaasecenesssseteny 52 5 2 Rotor Synchronization Operation seeeeseeseseseesererereereserersrerustererererrerererersreenererereees 52 5 3 Rotor Speed Controller Accessory Operation ssseeeesseeesseresrsrrersrrsrerreerernsrerrserreseees 56 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NMR 4 Table of Contents 5 4 Chapter 6 1 6 2 6 3 6 4 6 5 6 6 6 7 6 8 6 9 6 10 6 11 6 12 6 13 6 14 6 15 6 16 6 17 6 18 6 19 6 20 6 21 6 22 6 23 6 24 6 25 6 26 6 27 6 28 6 29 6 30 6 31 6 32 6 33 6 34 6 35 6 36 6 37 Variable Temperature Operation with Solids oo eee cece cseeeceseeeceeeeseeeeeeseeeeees 58 6 Solid State NMR Experiment ccccssssececeeseeeeeeeeeeeeeeesseeeeeeeees 60 XPOLAR Cross Polarization UNITY o cccccccccccsssceccecesssceseeceessaeeeecsesseseeeeesenaes 61 XPOLAR1 Cross
124. olarization pw is in microseconds p1 is the initial observe pulse direct polarization usually set to a 180 inversion pulse or the initial proton pulse usually set to a 180 pulse cross polarization p1 is in microseconds p2 is the cross polarization contact time in microseconds p3 is a pulse in microseconds for an X nucleus only spin lock following p2 dm should be set to nny The decoupler has a maximum duty cycle of 20 d2 is delay between p1 and pw for inversion recovery if pdp n If pdp y d2 is a delay for interrupted decoupling for protonated carbon suppression d2 is in seconds srate is the sample spinning rate in Hz toss set to y invokes timed spin echoes to suppress spinning side bands level1 controls decoupler power during cross polarization level1f controls fine decoupler power during cross polarization 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 62 Chapter 6 Solid State NMR Experiments level2 controls decoupler power during acquisition level2f controls fine decoupler power during acquisition time levell and level2 control decoupler power and should be used for Hartmann Hahn matching The decoupler is set with the config display and can be either class C with a maximum level of 255 or linear with a maximum of 63 0 is the minimum power on UNITY systems and 16 is the minimum on UN TYJNOVA and UNITYplus systems levellf and level 2f are only active for linear attenuato
125. ommended e crossp is the decoupler linear modulator setting during cross polarization and the initial 90 pulse 0 minimum voltage to 4095 maximum voltage The range is similar to dipolr Doubling crossp doubles the cross polarization field strength in kHz and halves the initial proton 90 pulse For UN YINOVA and UNITYplus the recommended settings are dblv12 to n dpwr to the maximum power rating of the probe the cross polarization field strength controlled by crossp and the decoupling field strength controlled by dipolr If dblv12 is set to n the parameters dolv12 and cppwr are hidden and can be ignored Beware UN TYINOVA and UNITYplus sequences as written have not been fully tested with a UNITY system Consult the applications laboratory for support Additional parameters for xpolar1 on YNTYINOVA and UNITYplus systems e p180 greater than 0 0 implements an additional prepulse followed by a delay d2 For direct polarization xpol n p180 is an observe pulse For cross polarization xpol y p180 is a proton pulse p180 is in microseconds e perho greater than 0 0 implements an additional observe pulse following the contact time Use pcrho for observe Tip measurements The units for pcrho are microseconds e dm should be set to nny The decoupler has a maximum duty cycle of 20 e pdp set to y implements interrupted decoupling for a period d2 to cause suppression of protonated carbons e d2 is set greater than 0
126. on pw is the observe 90 pulse xpol n or the proton 90 pulse Gool y pwisin microseconds pwx is the mixing pulse in microseconds If xpol n pwx pw if xpol y itis set to the observe 90 pulse srate is the measured MAS spinning speed CPCOSYPS does not require rotor speed control However with rotor speed control set sw1 equal to srate to remove spinning sidebands in both dimensions phase 1 2 for the hypercomplex method use wft 2da for the 2D FT phase 3 for TPPI use wft2d 1 0 0 0 for the 2D FT Reference Wu G Wasylishen R E Organometallics 1992 11 3242 6 16 CPNOESYPS Cross Polarization Phase Sensitive NOESY The CPNOESYPS sequence is a 3 pulse 2D exchange correlation sequence similar to the high resolution NOESY experiment CPNOESYPS can be run as a direct polarization experiment or the first 90 pulse can be substituted with a cross polarization pulse element Figure 36 is a diagram of this sequence For CPNOESY cross peaks occur between resonances that share mutual through space dipolar coupling or interact through weak spin diffusion Coupling can be enhanced with the insertion of rotor synchronized 3 pulses during the mixing period Cross peaks are also observed between resonances with chemical exchange and CPNOESYPS can be used to observe exchange between static powder spectra Use XNOESYSYNC to characterize molecular motion in the presence of MAS Applicability CPNOESYPS found in use
127. or spin silicon nitride rotors faster than 9500 Hz For samples that have densities above 3 0 g cc decrease the maximum spin rate by 35 It may be necessary to increase the bearing pressure for ill behaved samples or for very high spinning speeds Provided that the two flowmeter valves are fully open they require no adjustment at any time Never adjust the spin rate with the flowmeter CAUTION To prevent damage to the rotor or bearing always smoothly shut off the rotation gas using the rotation pressure regulator before turning off the bearing gas using the bearing pressure regulator To remove a sample take care to decrease the rotor speed smoothly At all times that rotation air is flowing bearing air should read at least 28 psig 1 9 bar Only when the rotation air is completely off should the bearing be carefully decreased to zero Overcoming Imbalance Most of the spinning problems encountered with filled rotors result from imbalance caused by the sample material A damaged rotor might be at fault but that can be eliminated by always checking the spinning quality of the empty rotor before packing it with the sample material Discard damaged rotors If a packed rotor does not spin properly at first inspect it to see if the sample has been disturbed Part of the sample may have broken loose and been thrown out of the rotor in which case repacking might be the solution Sometimes loose material balances itself if kept in the rotor
128. order 1p phase correction of the lineshape Values of tau1 and tau2 as short as 10 microseconds can be used Set t au2 less than t au1 to observe the spin echo and process data with 1sfid less than 0 to begin acquisition at the top of the spin echo The phase cycle is that of Rance and Byrd Figure 43 shows a diagram of the HAHNCP1 sequence VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 23 HAHNCP1 Spin 1 2 Echo Sequence with CP lt if xpol y gt cntct 2 pwx tpwrm tau2 t TX tau1 au d a pw cntct dipolr crossp d Dec A B c c Figure 43 HAHNCP1 Pulse Sequence Applicability HAHNCP1 is available only on YN YINOVA and UNITY plus It is found in userlib Macro The macro hahncp1 converts a parameter set obtained by XPOLAR or XPOLARI for the spin echo experiment Observe and decoupler power levels and the 90 pulse width are retained as well as the value of xpol By default pwx pw Fine calibration of pwx is recommended t aul t au2 10 in microseconds Parameters HAHNCPI uses UN YINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters xpol is set to n for direct polarization or set to y for cross polarization pwx is the observe 90 pulse in microseconds The 180 pulse is 2 0 pwx taul is the delay in microseconds between the 90 pulse contact pulse if xpol y and the
129. oton is an abundant spin Where rare spin conditions apply the damping box can be removed in which case the ring down time will be longer 45 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 4 2 Runn 4 2 Running the FLIPFLIP Pulse Sequence ing the FLIPFLIP Pulse Sequence The FLIPFLIP pulse sequence is set up by running the flipflop macro and setting the parameter phase2 to 0 as follows 1 Enter flipflopandsetd1 4 pw 1 5 fb le6 sw 2e6 np 128 tau 7 rof1l 1 5 rof2 0 2 Setphase1l 0 phase2 0 phaser 0 phfid Oor n trig n gain 0 nt 1 dp y Note that trig n is needed for HNTVINOVA and UNITYplus systems because the 500 kHz synching signal is not available otherwise set trig y 3 Acquire a FID and enter df to display both real and imaginary components Adjust the phase to minimize the imaginary signal If this is not possible check that the signal is on resonance 4 Enter phaser phfid phfid n and reacquire The imaginary channel should be minimal The real channel should show a FID pattern similar to Figure 13 ACQUISITION SAMPLE PROCESSING FLAGS sfrq 399 952 date Apr 1 93 lb not used il n tn DI file exp sb not used in n np 128 DECOUPLING gf not used dp y SW 2e 06 dn H1 awc not used trig y fb 1e 06 dof 0 lsfid 0 SPECIAL bs 16 dm n phfid not used srate 1542 ss 0 dpwr 30 fn 4096 temp 27 0 tpwr 54 tpwrf 3500 werr tauc 10 000 pw 1 500 0 wexp dE mp_at 0 000640 tau 3500 wbs d1 4 000 wnt phasel 0 tof 2
130. ound in SolidsLib version 2 1 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 9 XPOLXMOD1 Waveform Modulated Cross Polarization Macro The macro xpolwfgl1 converts a parameter set obtained with XPOLAR or XPOLARI for programmed decoupling Power levels and proton 90 pulse width are retained Default parameters include dseq tppm2 and dres 90 The value of dmf the decoupler modulation frequency is estimated with the relation dmf dipolr crossp 1 4 pw This value should be fine tuned for optimum decoupling Parameters xpolwfgl1 uses the UNITYplus parameters tpwr tpwrm dpwr cppwr crossp db1v12 pw and cntct see page 63 for a description of these parameters dm is set to nny to obtain decoupling dmn is set to ccp to obtain programmed decoupling during acquisition and set to c for continuous decoupling For dmm c the wfg parameters are hidden dmf is the decoupler modulation frequency and is set equal to one over four times the decoupler 90 pulse dmf must be calibrated and depends upon the value of dipolr The macro makes an estimate as described above Calibrate dipolr with a sample of dioxane and the macro h2cal1 or to fine tune obtain spectra versus dmf and choose that with the greatest narrowing dres is the waveform resolution and it depends on the decoupler waveform Waveforms Three waveforms are included in the shapelib of Solids1lib 2 1 For each waveform name DEC set dseq
131. parated Local Field Spectroscopy 85 The DIPSHFT1 pulse sequence is the separated local field spectroscopy SLF experiment of Munowitz and Griffin using windowless MREV8 as described by Zilm Figure 38 is a diagram of the sequence Applicability DIPSHIFT found in user1ib is available for UNITVINOVA and UNITYplus systems VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 18 DIPSHFT1 Separated Local Field Spectroscopy cntct lt if refocus n gt tpwrm d2 at Tx periods srate F pp pw cntct dipolr crossp di Dec L tau 0 to ni 1 times c Figure 38 DIPSHFT1 Pulse Sequence Macro The macro dipshft1 converts a parameter set obtained with XPOLAR or XPOLARI for DIPSHFT1 Power levels and the proton 90 pulse width are retained The value of pp is estimated from pw dipolr and crossp Further calibration of pp may be necessary Parameters refocus and setup are both set to n Parameters dipshft1 uses YN TYINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters pp is the proton 90 pulse in microseconds used for MREV8 proton decoupling during the evolution period dipolr sets the pulse power level Typically dipolr is set at the maximum decoupling field strength of the probe and pp is set as short as possible pp can be e
132. perative when array Use the vacplist macro instead to display the vacp array Reference Peersen O Wu X Kustanovich I Smith S O J Magn Reson 1993 104 Series A 334 75 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 11 XPOLEDIT1 Solids Spectral Editing 6 11 XPOLEDIT1 Solids Spectral Editing XPOLEDIT1 provides for spectral editing of CH3 CH CH and C carbons by use of differences in their cross polarization properties The sequence provides a 180 phase shift during the contact time depolarization followed by a return to the original phase repolarization Individual carbon types can be nulled with appropriate delays p3 and p4 and spectral editing can be achieved by addition and subtraction of subspectra obtained with the different delays Figure 31 is a diagram of the XPOLEDIT1 sequence cntct p3 p4 tpwrm at Tx p3 pw fm Figure 31 XPOLDIT1 Pulse Sequence Applicability XPOLEDIT1 is available on N YINOVA and UNITYplus and present in userlib Macro The macro xpoledit1 converts a parameter set obtained with XPOLAR or XPOLAR1 for XPOLEDIT1 Power levels and pulse widths are retained Parameters XPOLEDIT1 makes use of the YNTYZNOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cnt ct See page 63 fora description of these parameters p3 is the depolarization time in microseconds The phase of the proton channel is reversed p4
133. polarization or xpol is setto y for cross polarization e pw is the observe pulse for direct polarization or the proton 90 pulse for cross polarization pw is in microseconds e cntct is the cross polarization contact time in microseconds e tpwr is the observe power setting 16 dB minimum to 63 dB maximum power e tpwrm is the observe linear modulator setting 0 minimum voltage to 4095 maximum voltage The parameter t pwrm is linearly proportional to the applied transmitter voltage doubling t pwrm halves the value of the pulse width e dpwr is the decoupler power setting for decoupling during the acquisition period 16 dB minimum to 63 dB maximum power See also cppwr and dblv12 below e dipolr is the decoupler linear modulator setting during acquisition 0 minimum voltage to 4095 maximum voltage The value of dipolr is linearly proportional to 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 64 Chapter 6 Solid State NMR Experiments the applied decoupler voltage doubling dipolr doubles the decoupler field strength in kHz e cppwr is the decoupler power setting during cross polarization and during the initial proton 90 pulse 16 dB minimum power to 63 dB maximum power The parameter cppwr is active only if dblv12 y If dblv12 n only dpwr is used e dblv12 set to y activates cppwr during cross polarization and the initial proton 90 pulse For UN YINOVA and UNITY plus setting dblv12 to n is rec
134. probe to 2H as described in the probe installation manual and then connect the otherwise unused lock cable to the observe channel of the probe 3 Use the interactive acquisition window to lock the spectrometer in the usual way and then adjust the important shims Usually it is only important to adjust X Y Z1 Coarse and Z2 Coarse 4 When finished shimming turn the lock off and adjust ZO so that the lock signal is on resonance This ensures that the field will be in the same position as used for liquids work so that the usable frequencies will be the same 5 Set lpower 0 This ensures that at the time of the next su command the lock transmitter is deactivated removing a source of potential frequency interference Pulse Width Calibration Although it is possible to perform pulse width calibrations on the sample of interest using solid state echo experiments calibrations done in this manner can be misleading For example there is not usually a null at the 180 pulse for quadrupolar nuclei As a general tule all pulse width calibrations should be made with solutions A sample of D2O can be used for 2H work while a 1 M solution of a salt in water can be used for other nuclei such as 23Na The acquisition controller board of the YN TYZNOVA has a timing resolution of 12 5 ns which limits your ability to specify a pulse width to increments of 0 0125 us Similarly the UNITYplus and UNITY have a timing resolution of 25 ns thus limitin
135. quids high band amplifier is boosted to an upper limit of 1 kW by a tuned linear amplifier The main components are a wideband ADC high band high power amplifier fine attenuator and pneumatics tachometer control box For UNITY and VXR S systems the sync module is used to synchronize acquisition to the master clock Also the liquids observe receiver is replaced by a wideband observe receiver described in Wideline Solids Module page 34 4 1 CRAMPS Multipulse Module Hardware The main CRAMPS multipulse module hardware is the motor control box 1 kW amplifier sync module UNITY and VXR S systems only and the CRAMPS probe Motor Control Box The motor control box is used to adjust the output load and tuning of the 1 kW proton amplifier see below It consists of a selector switch with 3 positions TUNE LOAD and STANDBY or AUX and two 3 position toggle switches COARSE and FINE The toggles are momentary contact and can be pushed sideways in two directions which are designated IN and OUT The box moves the end plates of the cavity in or out to affect the tuning process In each of the active positions the plate position is displayed on a meter on the box 1 kW Amplifier The decoupler amplifier uses an EIMAC cavity tube Thus the amplifier has both low voltage power supplies and a high voltage supply The high voltage power supply EHT is 2 3 kV and is produced by the unit in the bottom of the solids cabinet Low voltag
136. r 15 polycrystalline compounds 14 polyethylene as a secondary spectral reference 31 polymers 70 97 powder materials in a rotor 19 pattern 42 power button 37 power control box 17 pp parameter 86 preparation pulse flip angles 100 programmed decoupling 71 projectile hazard from spinning rotor 20 prosthetic parts warning 8 115 VNMR 6 1C User Guide Solid State NMR proton carbon heteronuclear chemical shift correlation 69 channel modulation 72 chemical shift selection pulse 70 multiple quantum spectrum 108 relaxation studies 39 spin diffusion 70 T measurement 30 62 wideline experiments 38 wideline spectrum 71 protonated carbon suppression experiment 29 60 ptext command 39 Pulse Sequence Controller board 50 101 102 103 105 pulse width calibration 26 40 Pulsed button 37 pulsed mode amplifier operation 36 pure chemical shift spectra 103 pw parameter 62 67 70 80 82 83 96 98 101 102 103 104 105 106 108 109 pw90 parameter 40 pwx parameter 66 82 83 85 88 90 93 94 Q QUADECHO sequence 42 quadrature correction 99 quadrupolar 95 interaction 14 nuclei 39 quadrupole echo 96 pulse sequence 95 quasi elliptical filters 35 R r2selpuls1 macro 85 R2SELPULS1 pulse sequence 84 radio frequency emission regulations 11 rare spin response 15 rcontrol software 54 rdflag parameter 90 receiver gating 36 REDOR pulse sequence 89 redor macro 90 reference substan
137. r ga When acquisition is finished enter dssh to display the results Select the spectrum with the maximum signal and set leve11 to the value 1 for this spectrum in the next step we reduce level1f 5 Array level1f with the full range 0 to 4000 in steps of 500 6 Enter ga and when acquisition is finished enter dssh Select the value of level1f that gives the maximum signal For an even closer match array 1eve11f in smaller steps around this value For systems equipped with an observe fine attenuator tpwrf can also be used 2 10 Optimizing Parameters and Special Experiments 27 This section provides information on parameters used for specific optimizations such as contact time and repetition rate Also included in this section are special experiments for the high performance CP MAS module With each of these experiments is a sample spectrum and an illustration of the XPOLAR pulse sequence used Contact Time Array For samples in which cross polarization is used the contact time that is the time during which cross polarization occurs must be optimized with the parameter p2 This is necessary because two processes are occurring simultaneously e Build up of magnetization due to cross polarization e Loss of magnetization due to rotating frame relaxation VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 10 Optimizing Parameters and Special Experiments Thus a time exists for which an optimum in the magne
138. r to the manuals supplied with the magnet for the size of a typical 10 gauss stray field This gauss level should be checked after the magnet is installed WARNING Only qualified maintenance personnel shall remove equipment covers or make internal adjustments Dangerous high voltages that can kill or injure exist inside the instrument Before working inside a cabinet turn off the main system power switch located on the back of the console WARNING Do not substitute parts or modify the instrument Any unauthorized modification could injure personnel or damage equipment and potentially terminate the warranty agreements and or service contract Written authorization approved by a Varian Inc product manager is required to implement any changes to the hardware of a Varian NMR spectrometer Maintain safety features by referring system service to a Varian service office WARNING Do not operate in the presence of flammable gases or fumes Operation with flammable gases or fumes present creates the risk of injury or death from toxic fumes explosion or fire WARNING Leave area immediately in the event of a magnet quench If the magnet dewar should quench sudden appearance of gasses from the top of the dewar leave the area immediately Sudden release of helium or nitrogen gases can rapidly displace oxygen in an enclosed space creating a possibility of asphyxiation Do not return until the oxygen level returns to normal WARNING Avoid h
139. r1lib is available only on UN TYINOVA and UNITYplu Macro The macro cpnoesyps converts a parameter set obtained with XPOLAR or XPOLARI for the solids 2D exchange correlation experiment CPNOESYPS Power levels and the proton 90 pulse width are retained Default parameters set up for a phase sensitive 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 82 Chapter 6 Solid State NMR Experiments 83 _ 2 pwx lt if rfdr y gt X Y X Y Y X Y X L _ J n 1 srate TS re Es cnttt wx Pe tpwrm Tx d2 mix at pw cntct dipolr crossp Dec d ee eg A c Figure 36 CPNOESYPS Pulse Sequence hypercomplex acquisition with rfdr setto y Also sw1 is set equal to sw and xpol y Parameters cpnoesyps uses NITYINOVA and UNITYplus parameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters xpol is set to n for preparation by direct polarization xpol is set to y for preparation by cross polarization pw is the observe 90 pulse xpol n or the proton 90 pulse xpol y pw isin microseconds pwx is the length of pulses two and three and is to pw if xpol n pwx is in microseconds mix is the mixing period in milliseconds see also rfdr below Use caution because dm y during the mix period may lead to an una
140. ra The second argument of analyze is the name of the arrayed parameter which in the case of VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 1 XPOLAR Cross Polarization UNITY 13C T p experiments using the xpolar sequence is the parameter p3 for xpolar1 use pchro The third argument is the type of analysis to be performed for example use t 2 for the exponentially decreasing data points of a Tup experiment The fourth argument list results in the construction of the file analyze 1list where the summary of the data analysis and calculations are stored in the current experiment A hard copy can be obtained just as with any other text file The graphical display of the data can be viewed on screen by using the command exp1 or plotted with the command pexp1 Measurement of the H T4 through Cross Polarization Proton T can be measured using the XPOLAR pulse sequence by performing a standard inversion recovery experiment on the protons followed by cross polarization of the remaining IH magnetization to the carbons Figure 24 is a diagram of the pulse sequence The xpolar macro sets up parameters for the XPOLAR pulse sequence xpol y Joel p1 pw level1 f ta d d2 p2 136 i Figure 24 Pulse Sequence for Measuring H T Parameters xpol is set to n for direct polarization or set to y for cross polarization pw is the observe pulse for direct polarization or the proton 90 pulse for cross p
141. rameters tpwr tpwrm dpwr cppwr dipolr crossp dblv12 pw and cntct See page 63 for a description of these parameters dbcpflag is set to y to do double cross polarization A Hartmann Hahn match between the observe nucleus and third channel nucleus follows a standard cross polarization The second cross polarization drains polarization from the observe nucleus and lowers the signal intensity If docpflag is set to n this second cross polarization is omitted A positive difference signal is obtained by subtracting spectra with dbcpflag n minus dbcpflag y or by dbcplfag y and third channel irradiation off minus on resonance dn2 is the third channel nucleus dof 2 is the third channel decoupler offset in Hz dof2 is best obtained by direct observation of the spectrum of the third channel nucleus dpwr2 is the third channel coarse attenuator setting 16 dB to 63 dB crossp2 is the third channel linear modulator setting 0 to 4095 The parameters crossp and crossp2 determine the Hartmann Hahn match for the dilute spin cross polarization The dilute spin Hartman Hahn match is determined with DOUBLECP1 Array the value of crossp2 The Hartmann Hahn match corresponds to the minimum signal intensity cntct2 is the contact time for the dilute spin cross polarization in microseconds References Schaefer J Stejskal E O Garbow J R McKay R A J Magn Reson 1984 59 150 Stejskal E O Schaefer J McKay
142. ransfer of energy from the polarized abundant spins to the rare spins the rare spin field is turned off and the resulting signal observed under conditions of high power proton decoupling The recycle time is then set according to the proton T which is usually much shorter than the rare spin T The polarization transfer can give an increase in sensitivity The rare spin response is enhanced by a factor of up to the ratio of the magnetogyric ratios of the two spin systems For the Bes IH system this is a factor of 4 However as the enhancement is distance related caution should be exercised in using the cross polarization experiment for quantitative analysis 1 3 Solids Modules Probes and Accessories 15 Varian supplies a complete line of solid state NMR modules probes and accessories Solids modules include CP MAS wideline CRAMPS multipulse and complete solids CP MAS wideline and CRAMPS Multipulse hardware and operation are covered in Chapters 2 3 and 4 respectively of this manual The Varian complete solids module is capable of performing all experiments possible with the Varian CP MAS wideline and CRAMPS multipulse modules The major components of complete solids module are the following UNITYTINOVA or UNITYplus System Wideband ADC with Sum to Memory Solids cabinet High band amp low band 1 kW amplifier Pneumatics tachometer box UNITY or VXR S System Wideband ADC Solids cabinet High band amp low band 1 kW amp
143. ransients it is necessary to repeat the FLIPFLIP sequence to readjust the power for the desired 90 pulse length which may have altered as a result of tuning out the phase transients VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 29 HS90 90 Degree Phase Shift Accuracy phase phase2 r pw acq pw acq di rof2 dau V rofi rof2 dtau V rofi LI LI L np 4 times tau W tau Figure 46 FLIPFLOP Pulse Sequence Macro The macro flipflop recalls the sequence and a modified parameter set Parameters pw is the pulse length in microseconds usually set to a 90 pulse phasel1 is the phase of the first 90 pulse and is set to 0 x phase2 is the phase of the second 90 pulse and is set to 2 x trigissetto y or n depending on the system On UN YINOVA and UNITYplus the pulse sequence in not tied to any internal triggering mechanism and t rig should always be set to n On UNITY and VXR data acquisition is triggered to an internal 500 kHz clock so trig must be set to y and the signal of the 500 kHz clock plugged into the external trigger input located on the Pulse Sequence Controller board np is usually set to 128 points tau is 20 microseconds 6 29 HS90 90 Degree Phase Shift Accuracy At the completion of use of the multiple pulse tune up sequences FLIPFLIP and FLIPFLOP the spectrometer is tuned for multiple pulse experiments An opt
144. re Corrections for CORY24 Preparation Pulse Acquisition M 0 degrees 1 1 N2 1 1 0 90315 2 0 0 1 Un 3 1 V2 1 1 0 9045 4 0 0 1 1809 The preparation pulse flip angles are set in the pulse sequences by scaling the flip time with 25 nanosecond resolution based typically on a 1 5 microsecond 90 pulse set during the tune up procedure Unlike conventional multiple pulse experiments where after the calibration with tune up sequence the experiments are run off resonance to minimize interference from the pedestal and maximize resolution data for the phase cycled experiments need to be acquired with the transmitter positioned roughly in the middle of the spectrum The data obtained from a multiple pulse experiment is processed the same as data obtained from any 1D experiment with one key exception the inherent scaling factor in multiple pulse experiments The contraction of the chemical shift scale is accommodated in the NMR software by the macro scalesw and the parameter of the same name References Waugh J S Huber L M Heaberlen U Phys Rev Lett 1968 20 180 Mansfield P J Phys C Solids State Phy 1971 4 1444 Rhim W K Elleman D D Vaughan R W J Chem Phys 1973 59 3740 Burum D P Rhim W K J Chem Phys 1979 71 944 Barbara T M Baltusis L J Magn Reson 1994 106 182 6 27 FLIPFLIP 90 Degree Pulse Calibration Two calibration experiments FLIPFLIP and FLIPFLOP test
145. re necessary Make sure that the 30 60 MHz 1 4 wavelength cable is on the magnet leg Enter setup H2 d2o0 dm n su Tune the probe as described in the probe installation manual Now instead of the observe channel connect the lock channel to the probe Lock the spectrometer in the usual way The spectrometer can now be shimmed using acqi but there is no point trying to obtain a resolution that is markedly better than the lines to be observed so that only the gradients X Y Z1 Coarse and Z2 Coarse need be optimized Make sure that the lock and spinner are deactivated by selecting LOCK OFF SPIN OFF SPIN 0 and setting lockpower 0 Replace the lock connection with the observe channel Check the tuning and then make sure that the probe is connected to the Normal position on the preamplifier If not already done reset the solids cabinet and make sure the broadband 1 kW amplifier is on and that no interlocks are activated Set the switch panel so that the LOWBAND is on HI POWER Set sw 1E5 pw 2 np 1E4 d1 4 nt 1 Set tpwr to the standard value for the system If no value has been determined previously set tpwr 55 Set gain n and acquire a spectrum Phase correct the result and ensure that the spectrometer is working correctly If necessary use movet of to place the D O signal exactly on resonance Check these adjustments by reacquiring a spectrum Array pw to determine the 180 or 360 pulse width Set gain y b
146. rotor speed save the data log file or exit to the main menu To save the data log file DAC and rotor speed values choose the L option from the main menu You can specify the number of data points to log 4000 points maximum and a control loop divisor N For example if N is set to 10 a DAC and rotor speed pair is logged every 10th time through the control loop Log data is written to disk only after termination of the closed loop control session and confirmation by the user Configuration Routines The configuration F choice at the main menu displays the current gain settings used in the closed loop control process and allows you to change them Besides the gain values the configuration routines allow you to set the following e Loop delay set in milliseconds e Increment clamp value for the loop increment The loop delay specifies a time delay between outputting to the DAC and reading the rotor speed Note that too short a time may lead to wild oscillations in the closed loop mode when the gain settings are large The increment clamp value sets the maximum change to the DAC word and is a useful type of adaptive gain that can allow gain settings that produce good control so long as the change in set point is not too large Typical ranges for the gain settings are shown in Table 7 G3 and G4 set to 0 produce good control when the ranges shown in the table are used for the other gains Table 7 Rotor Controller Gain Setting and
147. rovides a pulse as a trigger to a circuit on the Acquisition Controller or Pulse Sequence Controller board The dark to light edge can be used in three ways 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 50 Chapter 5 Solid State NMR Accessories 51 Filter Flow meter valve Angle adjust tool yy g j ee ee Rotation drive to probe eeneg JH Si g Weess Drive pressure CH regulator and gauge Bearing to probe lt j CO Rotation trigger adjust E e Body N2 to probe CH l ETH 4 bie gt Bearing pressure fer al D 2 pa pet be CH E se On To eject port of magnet _ Tachometer counter N2 supply in regulator and gauge Purge to heat exchanger e Body pressure regulator and gauge Figure 17 Pneumatics Tachometer Box for CP MAS Probes e The time between successive edges can be measured note that the edges are always in the same sense so that this interval is one rotor period This has a precision of 50 ns This is shown as mode 1 in Figure 18 An event can be triggered on the nth edge in all cases here n is an integer In this mode the rotor is providing an external timing event to the Acquisition Controller or Pulse Sequence Controller board This provides a means o
148. rs and they give an additional 6 dB range for UNITY systems and 60 dB range for UN TYINOVA and UNITYplus systems divided into 4095 steps 1eve11 and level2 override dpwr References Cross Polarization Technique Pines A Gibby M G Waugh J S J Chem Phys 1973 59 569 Stejskal E O Schaefer J Waugh J S J Magn Reson 1977 28 105 Spinning Sidebands Herzfeld J Berger A E J Chem Phys 1980 73 6021 Dixon W T J Magn Reson 1981 44 220 Dixon W T J Magn Reson 1982 49 341 Dixon W T J Magn Reson 1985 64 332 Protonated Carbon Suppression Opella S J Fry M H J Am Chem Soc 1979 101 5856 Relaxation Times Schaefer J Stejskal E O Buchdahl R Macromolecules 1077 10 384 6 2 XPOLAR1 Cross Polarization YI NOVA amp UNITY plus 63 XPOLARI is a version of XPOLAR that has been modified for UNTVINOVA and UNITY plus systems It contains the same functionality as XPOLAR described on page 59 with the exception that the parameters that control the attenuators and linear modulators have been renamed Figure 25 is a diagram of XPOLARI For UNYINOVA and UNITYplus it is recommended that you control the power levels associated with cross polarization entirely with the linear modulator which has a range of 60 dB and set the coarse attenuator to a value corresponding to the maximum specification of the probe The parameter 1eve11 has been disabled it can be re en
149. s parameter have not been fully checked Use the display command to confirm units tlinit is the initial delay increment The units of this parameter have not been fully checked Use the display command to confirm units Reference Baum J Munowitz M Garroway A N Pines A J Chem Phys 1985 83 2015 6 35 SPINDIFF Spin Diffusion in Solids Tx 109 SPINDIFF is a pulse sequence for 2D exchange spectroscopy in which spin diffusion is occurring in solid dense homonuclear dipolar coupled spin systems Figure 54 is a diagram of the sequence 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u 1 0u jo gt 2 Ja V gt Isa P 3 g gt 2 gt V gt oa 9 gt Ri OO CH sr CH oO CH mMm O Dei bel CH DO CH kel st bel CO 1 0s CH oO CH CH CH di dau pw pw pw pw pw pw pw pw pw pw pw pw pw w pw pw pw pw pw dtau dtau dtau dmix dtau dtau dtau dtau dtau tau dtau tau dau tau dtau tau dtau tau tau dtau tau dtau tau dtau 2 0p 7 A Figure 54 SPINDIFF Pulse Sequence Macro The macro spindiff retrieves a parameter set suitable for the SPINDIFF experiment Parameters The parameters used are analogous to those used in other multiple pulse experiments pw is the 90 pulse length in microseconds tau is time delay between the pulses in
150. se should advance the phase by 90 but also keep M 0 orthogonal to the unit vector n The initial magnetization vectors preparation pulses for MREV8 are listed in Table 8 Table 8 Multiacquisition Quadrature Corrections for MREV8 Preparation Pulse Acquisition M 0 degrees 1 0 1 0 900 2 1 V2 1 0 1 135979 3 0 1 0 90180 4 1 V2 1 0 1 4590 For BR24 the average chemical shift Hamiltonian lies along 1 1 1 and again the magnetization traces a elliptical path However the principal axes are inclined 45 to the rotating frame and the minor axis is 1 3 of the major axis The best choice for preparation pulses therefore requires 45 phase shifts to the transmitter Even without small angle phase shifts a 45 y pulse can be used to reduce pedestals and spin locked magnetization which is considerably more intense than for MREV8 A four step method for BR24 akin to that for MREV8 can be implemented by using the preparation pulses listed in Table 9 For the pulse sequence CORY 724 the preparation pulses for a four step quadrature correction method are listed in Table 10 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 27 FLIPFLIP 90 Degree Pulse Calibration Table 9 Multiacquisition Quadrature Corrections for BR24 Preparation Pulse Acquisition M 0 degrees 1 1 V2 1 1 0 90315 2 1 V6 1 1 2 145599 3 1 V2 1 1 0 90135 4 1N6 1 1 2 3545 Table 10 Multiacquisition Quadratu
151. signal derived from the master oscillator Its output is connected to the EXT TIMEBASE input on the output board A pulse sequence can delay until the next clock edge by using the pulse sequence element xgate 1 0 at an appropriate point This is commonly used in multipulse sequences to improve stability when running high resolution experiments for a long time The VVMR User Programming Manual describes its use in more detail CRAMPS Probe The standard CRAMPS probe has a VT range from 120 to 160 C and can typically tune from the 9F frequency to that of H It is optimized for H and is essentially background free for that nucleus In order to achieve low H background many components are made of a fluorocarbon so that a high 9F background exists This may not necessarily preclude 19F line narrowing experiments but care must be taken WARNING Dangerous high rf voltage in the system can cause serious injury or death To avoid electrical shock completely turn off rf and disconnect all rf cables before removing the probe WARNING Spinner rotors have very high kinetic energy and can disintegrate at any time To prevent possible cuts or blindness wear a certified full faced safety shield and cover all exposed skin while observing a rotating sample The CRAMPS probe has a 5 mm rotor and is designed to spin to 8 kHz The probe does not have high sensitivity because sensitivity is not normally an issue in multipulse experiments where pr
152. sor position enter tshift followed by go or ga Other spectra can now be acquired using these parameters Obtaining a Wideline Spectrum of Z7Na Sodium does not normally have a parameter set in st dpar so it is necessary to call up some standard set and modify it The easiest way to do this is shown in step below 1 Enter setup H2 d2o0 tn Na23 dm n su 2 Set up the probe with the correct coil and tuning rod if any and put in a sealed sample of NaCl 1 M in H20 Tune the probe as described in the probe installation manual 3 Follow step 5 through step 12 in Obtaining a Wideline Spectrum of Deuterium page 41 4 Remove the sealed sample of NaCl 1 M in H30 and replace it with the sample to solid sodium nitrate 5 Tune the probe and enter ssecho to convert to the QUADECHO sequence and acquire 16 transients using a d1 of 1 second 6 Process the spectrum the same as for deuterium except that the center of the powder pattern is the center of the highest line Hints for Performing Wideline Experiments If a powder pattern shows more than 3 4 asymmetry in the height of the horns check that the sample is centered in the coil If this is the case check the tuning of the probe If neither results in a significant improvement shift the transmitter position 1000 Hz towards one horn Finally recalibrate the 90 pulse with a solution sample then retune the probe to the same reflected power level T can be
153. ssrererse 102 Table 10 Multiacquisition Quadrature Corrections for CORY 24 oo eeeessescceseeeeeeeeceseeeteeeeeene 102 7 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 SAFETY PRECAUTIONS The following warning and caution notices illustrate the style used in Varian manuals for safety precaution notices and explain when each type is used WARNING Warningsare used when failure to observe instructions or precautions could result in injury or death to humans or animals or significant property damage CAUTION Cautions are used when failure to observe instructions could result in serious damage to equipment or loss of data Warning Notices Observe the following precautions during installation operation maintenance and repair of the instrument Failure to comply with these warnings or with specific warnings elsewhere in Varian manuals violates safety standards of design manufacture and intended use of the instrument Varian assumes no liability for customer failure to comply with these precautions WARNING Persons with implanted or attached medical devices such as pacemakers and prosthetic parts must remain outside the 5 gauss perimeter of the magnet The superconducting magnet system generates strong magnetic fields that can affect operation of some cardiac pacemakers or harm implanted or attached devices such as prosthetic parts and metal blood vessel clips and clamps Pacemaker wearers should consult the user manua
154. st be able to measure very broad lines without any distortion It is for this reason that the transmitter power is high YH1 must be large enough to uniformly excite the entire spectrum The effects of a finite 90 pulse width may be investigated with simulations using the solids analysis software accessory With linewidths in excess of 100 kHz an increase in ADC speed is necessary In fact the typical spectral widths used often greatly exceed the linewidths because many spectra are obtained under over digitized conditions 3 1 Wideline Solids Module The wideline module for the Varian spectrometer modifies and extends the basic capability of the system in a number of areas The main components of the wideline module are the wideband ADC high power amplifier and the solids cabinet Wideline ADC Board A wideline analog to digital conversion ADC board is added to the system in addition to the standard ADC board Based on the spectral width the parameter sw the software determines which ADC board is to be used values of sw greater than 100 kHz will automatically use the faster ADC Two versions of the wideline ADC board exist e The newer version of the Wideline ADC board Part No 00 993350 00 was shipped with UNITYplus systems It has its own on board memory which consists of 2 x 64 Kword buffers maximum np is 131072 together with its own sum to memory STM circuitry Data is summed at this speed without additional overhead
155. stem 1 Enter mrev8 to set up the parameters for the MREV8 pulse sequence 2 Make sure that tau 3 5 rof1 1 5 and rof2 0 3 Enter go A FID should be obtained 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 48 Chapter 4 CRAMPS Multipulse Module Operation 49 If the FID is off resonance enter gf or enter acqi and adjust probe tune match to place the FID on resonance 4 Array tof from 1e4 to 1e4 in 1000 Hz steps 5 Set d1 20 and enter ga The resultant displayed spectra should show a single resonance that moves with tof Note that changing tof by 1000 Hz does not move the peak by 1000 Hz 6 Write down the value of tof that gives the sharpest line This is a guide for later use of the multipulse sequences For further information about the MREV8 pulse sequence refer to page 103 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Chapter 5 Solid State NMR Accessories Sections in this chapter e 5 2 Rotor Synchronization Operation this page e 5 3 Rotor Speed Controller Accessory Operation page 54 e 5 4 Variable Temperature Operation with Solids page 56 5 1 Pneumatics Tachometer Box The variable temperature VT Pneumatics Tachometer Box is used with Varian VT CP MAS probes The Pneumatics Tachometer Box handles all air gas supply distribution to the probe The supply line is permanently connected to the wall supply which must be clean dry air The wall supply should be at a
156. stimated with the equation pp pw crossp dipolr ifdblvl2 n setup is set to n to obtain a 2D spectrum normal operation setup is setto y to obtain a single t FID mrev8 is he number of MREV8 cycles set up is usually only used to observe the pulse sequence with dps for ni greater than 1 tau is the delay in microseconds associated with the MREV8 pulses Usually t au pp A single mrev8 cycle time is 8 pp 4 tau The f dwell time is equal to one mrev cycle Set the value of sw1 to 1 0 8 pp 4 tau Note that the maximum sw1 is limited by the mrev8 cycle time A small value of pp is preferred periods is an even integral number of rotor periods allocated to the evolution period The maximum evolution period FID ni must be less than this number of rotor periods If not an error message results noting the two times To correct the problem increase sw1 if possible or periods or decrease ni or srate along with actual spinning rate 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 86 Chapter 6 Solid State NMR Experiments srate is the actual spinning speed DIPSHIFT 1 benefits from rotor speed control but control is not required refocus setto y reveals the parameter sense If sense is set to r reverse a single observe refocusing pulse is applied at periods 2 and the evolution period precedes the this pulse If sense is set to f forward a simultaneous refocusing pulse is applied and evol
157. sures for the Varian 7 mm VT CP MAS probe at ambient temperature The spin rates shown are approximate values The actual spin rate varies depending on the properties of the sample and sample holder Use the following procedure for spinning all samples in high speed probes 1 Using your fingers insert either an end cap into the rotor to be spun Rotate the end cap while pushing it into the rotor Make sure the end cap is fully seated into the rotor 2 Make sure the bearing and drive air pressure are off 3 Carefully place the rotor with the end cap into the stator and install the probe into the magnet Turn the air bearing pressure to 28 psig 2 0 bar the rotor should start spinning slowly at 500 900 Hz 4 Slowly turn on the air drive pressure to 3 6 psig 0 25 bar and wait for 15 seconds to allow the rotor to stabilize 5 Gradually increase the air drive pressure to 7 psig 0 5 bar and again wait 15 seconds The spinning speed should gradually increase to about 2500 Hz 6 Slowly increase the air drive pressure to 14 psig 1 0 bar The spinning speed should reach about 3700 Hz 7 If rotor speeds faster than 3700 Hz are required slowly increase the air bearing pressure to 36 psig 2 5 bar Then increase the air drive pressure up to 34 psig 2 4 bar the rotor speed should reach about 7200 Hz Never apply air drive pressure above 72 5 psig 5 0 bar To avoid rotor explosions never spin zirconia rotors faster than 7200 Hz
158. t You may not redistribute anything in the user library in any form to anyone outside of your own organization without the express permission of the submitter Neither Varian Inc nor the submitter makes any warranty or representation of any kind express or implied with respect the material found in the user library This material is distributed as is and you assume the entire risk as to the quality reliability and performance of any software you choose to use In no event shall Varian Inc be liable for any consequential special incidental direct or indirect damages of any kind arising out of the use of software in the user library Use of any material in the user library shall constitute acceptance of these terms and conditions 6 1 XPOLAR Cross Polarization UNITY 59 XPOLAR is the basic sequence for CP MAS MAS and solid state relaxation measurements for UNITY systems for YN YINOVA and UNITYplus systems see page 63 XPOLAR can be run either as a standard single pulse experiment including the inversion recovery experiment with the parameter xpol set to n or more typically as a cross polarization experiment with the parameter xpol set to y The use of the XPOLAR sequence allows the removal of strong dipolar coupling by using a strong decoupling field applied during the acquisition of the data A characteristic of some nuclei in the solid state for example BC is a long spin lattice relaxation
159. t a convenient point such as at acomma near the right edge of the column a backslash is inserted at the cut and the line is continued as the next line of text This notation will be familiar to C programmers Note that the backslash is not part of the line and except for C source code should not be typed when entering the line Because pressing the Return key is required at the end of almost every command or line of text you type on the keyboard use of the Return key will be mentioned only in cases where it is not used This convention avoids repeating the instruction press the Return key throughout most of this manual Text with a change bar like this paragraph identifies material new to VNMR 6 1C that was not in the previous version of VNMR Refer to the document Release Notes for a description of new features to the software 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 12 Introduction 13 Other Manuals This manual should be your basic source for information about using the spectrometer hardware and software on a day to day basis for solid state NMR Other VNMR manuals you should have include e Getting Started e Walkup NMR Using GLIDE e User Guide Liquids NUR e VNMR Command and Parameter Reference e VNMR User Programming e VNMR and Solaris Software Installation All of these manuals are shipped with the VNMR software These manuals other Varian hardware and installation manuals and most Varian
160. t away from the OPTICAL OFF position and the OPTICAL OUT BNC connected with a coax cable to the EXTERNAL INPUT of the tachometer box Spinning Speed The parameter hsrotor is an experiment based parameter not a globally accessible parameter If you join another experiment to do rotor synchronization hsrotor may also need to be created in that experiment The spinning speed of the rotor may be displayed in the ACQUISITION STATUS window if the parameter hs rotor is setto y If the speed does not show enter hsrotor If hsrotor is undefined enter create hsrotor string andthenenter hsrotor y su to activate the spinning speed display Once the setup is complete the correct rotor speed should appear in the Acquisition Status window This checks that the rotor sync accessory is working CP MAS operates in the normal manner with rotor synchronization installed Manual entry of srate spinning speed in Hz is accepted however srate is updated at the end of each acquisition to reflect the actual spinning speed at the end of the acquisition At the start VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 5 3 Rotor Speed Controller Accessory Operation of each acquisition the initial spinning speed is noted If during acquisition the speed alters by more than 100 Hz and the interlock parameter in is set to y acquisition is halted The flexibility of rotor synchronization is mainly through the construction of pulse sequen
161. t of spinning sidebands As T9Br is very close in frequency to 13 it is easy to switch between the two nuclei The magic angle can easily be precisely set or checked as described below VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 5 Adjusting the Magic Angle 1 Enter tn Br79 to obtain the parameter set to observe Zpe If the following message appears Requested nucleus Br79 is not an entry in the nucleus table nuctabxXx where XX is 2d 3d or 4d then add this nucleus with the following VNMR commands Note that the first VNMR command invokes the vi text editor familiarity with this UNIX text editor is assumed vi vnmr nuctables nuctabxXxX Remember to use nuctab2d nuctab3d nuctab4d or nuctab5d in place of nuctabXx Add one of the following lines above the Br8 1 line e For 200 MHz systems add Br79 50 180 1 480e6 low yes 0 0 e For 300 MHz systems add Br79 75 180 1 480e6 low yes 0 0 e For 400 MHz systems add Br79 100 208 1 4842e6 low yes 0 0 Exit vi and then enter tn Br79 again No error should be generated 2 Load a rotor with KBr insert in the probe spin at 3 kHz and tune the system for 79Br Grinding the KBr crystals before packing the rotor is helpful 3 Set seqfil s2pul sw 1le5 at 0 02 nt 1 Enter ga to obtain a single transient spectrum Set the cursor on resonance and enter movetof 4 Set phfid 0 and enter gf Now open the acqi window click the FID button and observ
162. t rig should always be set to n On UNITY and VXR data acquisition is triggered to an internal 500 kHz clock so trig must be set to y and the signal of the 500 kHz clock plugged into the external trigger input located on the Pulse Sequence Controller board np is usually set to 128 points tau is 20 microseconds Reference Burum D P Linder M Ernst R R J Magn Reson 1981 43 463 6 28 FLIPFLOP Phase Transient Removal 101 The FLIPFLOP sequence 90 x acq 90 x acq is used to remove phase glitch or phase transient in the probe and pulse amplifier FLIPFLOP is the second sequence after FLIPFLIP normally used in setup To run a FLIPFLOP sequence rather than a FLIPFLIP sequence the only parameter that needs to be changed is the parameter phase2 which is now set to the value 2 Phase glitch is manifest as an in phase oscillation in the data A flip flop sequence alternately moves the magnetization from the Z axis onto the X Y plane using a train of pulses In the absence of any phase errors such as phase glitch the pattern generated by the FLIPFLOP experiment resembles a set of tram tracks Figure 46 is a diagram of FLIPFLOP Unlike the FLIPFLIP sequence which constantly rotates the magnetization in a single direction the FLIPFLOP train of pulses alternately flips the spins into the XY plane giving an NMR signal then back to the Z axis giving no NMR signal Following the adjustment of the phase t
163. tected The resulting current is amplified and used to toggle a Schmitt trigger that is the input to the external time base of the Acquisition Controller or Pulse Sequence Controller board Figure 19 Base of a Varian High Speed Spinning Rotor In principle detection in the Doty probe is the same Figure 20 shows a Doty double bearing rotor with a blackened sector on the inside of the lower drive cap The light pipes however are not as precise and the detection is more indirect thus giving a lower signal to noise ratio The photodetection is performed in the base of the probe and then transferred to an external amplifier with adjustable gain control The amplifier output is then sent to the tachometer box where it is further conditioned before being used to drive the Acquisition Controller board Figure 20 Doty Double Bearing Rotor or Pulse Sequence Controller board Specifications The specifications for the rotor synchronization accessory depend on both the probe and the electronics The values given below reflect those that can be obtained in optimum circumstances and as such do not imply a guarantee of performance If performance is severely degraded from these values the first remedy is to check the sector markings on the rotor because any lack of definition here will have profound effects on stability of the result Varian High Speed Spinning Probe Jitter in one TTL rotor period measured with an oscilloscope from f
164. tests hmb 2 Setdof 5e4 5e4 d1 10 3 Set level2 and Level2t such that the power output is about 80 watts 4 Enter ga 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 26 Chapter 2 CP MAS Solids Operation 5 When acquisition is finished measure the reduced coupling on each of the two spectra CAUTION To avoid damaging the probe do not exceed the probe decoupler power limit 6 Enter h2cal to calculate yB gt If necessary alter Leve12 to obtain a satisfactory value of YB gt 2 9 Adjusting the Hartmann Hahn Match Hartmann Hahn matching can be readily accomplished by using a sample of hexamethylbenzene HMB or adamantane These substances are not easily cross polarized However they have a high degree of symmetry and so once cross polarized gives rise to very intense signals 1 Load a rotor with HMB or adamantane insert it and spin it slowly about 2500 Hz for HMB or 1800 Hz for adamantane Adjust the spinning speed so that none of the sidebands of the aromatic carbons overlap the methyl resonance 2 Recall the test parameters by entering rt vnmr tests hmb Set xpol y Set pw to a 90 13c pulse Set p2 2500 at 0 05 d1 4 nt 4 3 Set level2 and leve1l12f as determined in the previous section and array level1 to pass across the Hartmann Hahn condition with the value of Level not to exceed leve12 Enter a fixed value of gain because Autogain cannot be used in an arrayed experiment 4 Ente
165. the speed variation can be determined from the broadening of pickets well down the fence in time Run a four transient FID and enter df With the FID now displayed use cursors and related commands to edit the display Measure the resolution of a picket at the start and at the end of the FID display Similar values indicate good spinning stability An alternative method of adjusting the magic angle uses 13C CP MAS of the standard sample hexamethylbenzene HMB which has two 13C resonances Of these the aromatic carbon line on the left side of the spectrum is extremely sensitive to the angular adjustment Figure 6 shows a typical spectrum including sidebands of the aromatic resonance Adjust the aromatic line for minimum linewidth and maximum intensity Figure 6 Typical Hexamethylbenzene HMB Spectrum VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 2 6 XPOLAR Pulse Sequence Once typical values for the minimum linewidths are established for any particular instrument these values can be taken as a reliable indication of proper angle Adjustment of the angle is neither necessary nor desirable if the first measurement indicates that the minimum linewidth has been achieved 2 6 XPOLAR Pulse Sequence The Varian supplied XPOLAR cross polarization pulse sequence is used to obtain CP MAS NMR spectra of solids This sequence is used for most experiments For more information on the XPOLAR pulse sequence see page 59 UNITY syste
166. the wideline package is for low band 12 to 200 MHz nuclei no IH or F high power amplifier is provided unless the CP MAS module or CRAMPS Multipulse module is also installed The 1 kW power amplifier is one of the following models e The AR Model 1000LPM10 covering the range of 9 MHz to 200 MHz with 60 dB of gain and a maximum output power exceeding 60 dBm over this range e The AMT Model M3201 covering a range of 6 MHz to 220 MHz with 10 dB of gain and a maximum power output exceeding 60 dBm over this range VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 3 1 Wideline Solids Module Status panel OC OO ol aa at 8 Sorensen Solids gt J ooo O O VT controller optional Low band 1 kW L P amplifier b Te Low band power supply O p CO e WS P CO High band 1 kW p 9 amplifier O e e H b High band ke EHT power supply Figure 12 Solids Cabinet Layout Open Front View Both amplifiers are linear with gating provided for noise blanking Operational details for the high power amplifiers are included in the manuals provided by the manufacturers of the amplifiers These should be read before operating the amplifier AR Linear Amplifier The AR linear amplifier is gated off whenever the receiver is gated on A time of at least 30 us is requir
167. thers Inclusion in this document does not imply that any particular feature is standard on the instrument UNITYTNOVA MERCURY Gemini GEMINI 2000 UNITY plus UNITY VXR XL VNMR VnmrS VnmrX Vnmrl VnmrV VamrSGI MAGICAL II AutoLock AutoShim AutoPhase limNET ASM and SMS are registered trademarks or trademarks of Varian Inc Sun Solaris CDE Suninstall Ultra SPARC SPARCstation SunCD and NFS are registered trademarks or trademarks of Sun Microsystems Inc and SPARC International Oxford is a registered trademark of Oxford Instruments LTD Ethernet is a registered trademark of Xerox Corporation VxWORKS and VxWORKS POWERED are registered trademarks of WindRiver Inc Other product names in this document are registered trademarks or trademarks of their respective holders Table of Contents SAFETY PRECAUTIONS E 8 Posting Requirements for Magnetic Field Warning SIQNS sssssnnsnnnnnsnnnnnnn 12 E g MAE siaiba gant sanwhaiipiahaeaiendanicnannidenstutsiendanuit 14 Chapter 1 Overview of Solid State NMR sssnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnn 16 EV BT esse ceceascssecescesveysiesthsaxeusesctoqncostnace gots A E EA 16 1 2 Spin Lattice Relaxation Time 0 eee cece cseeseceeceseceseeseeeeeeseeeeeeseseaseseesaeseeeaeenaes 17 1 3 Solids Modules Probes and Accessories ccccccccccccceccececeseeeeeescscsnscssnscececeeseeeeeeess 17 Chapter 2 CP MAS Solids Operation cssseecesseeeeeeeeeseeeeeeseseeeeee
168. time T1 To overcome this problem the abundant nuclei usually protons in the systems are polarized with a spin locking pulse and the polarization is then transferred VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 1 XPOLAR Cross Polarization UNITY to the rare spins by applying an rf field at the Larmor frequency of the rare spins that is of such magnitude as to make the energy levels of the abundant and rare spins the same in the rotating frame the Hartmann Hahn match condition Following a transfer of energy from the polarized spins to the rare spins the rare spin field is turned off and resulting signal observed under conditions of high power proton decoupling The recycle time is then set according to the proton T usually much shorter than the rare spin T For samples that use cross polarization the contact time the time during which cross polarization occurs should be optimized with the parameter p2 This is necessary because two processes happen simultaneously the magnetization buildup from cross polarization and the magnetization loss from rotating frame relaxation A time exists for which an optimum in the magnetization occurs The rising and falling exponential intensities can be analyzed with the contact_time macro which calculates both Toy and IH Tip Applicability XPOLAR is available on all systems Suppressing Spinning Sidebands NMR spectra at high magnetic fields often have significant spinning s
169. tion of complex spectra The sidebands can be eliminated using the TOSS TOtal Sideband Suppression technique The TOSS pulse sequence is selected by setting toss y in the XPOLAR sequence see Figure 8 Note that the parameter srate should be set to the spinning speed in Hz 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 28 Chapter 2 CP MAS Solids Operation 29 toss y xpol y toss y level2 pw level1 p2 Delay recipe including srate Figure 8 TOSS Experiment on Alanine Spectrum and Sequence TOSS is less effective at high spinning speeds Note that if suppression is not finished check that srate is correct TOSS uses 180 pulses based on pw It may be necessary to adjust pw to optimize the TOSS experiment Suppressing Protonated Carbon Interrupted Decoupling Off resonance decoupling and related experiments in which J coupling is involved are not routinely possible in solids because dipolar coupling as well as J coupling is present One experiment exists however that is used in solids to discriminate between carbon types and that is the protonated carbon suppression experiment of Opella and Fry In this experiment the decoupler is turned off for 40 to 100 us before acquisition to dephase the protonated carbons The technique is effective primarily for non mobile carbons mobile carbons like methyl groups are typically not suppressed as well Figure 9 shows a typical protonated carbon
170. tiple quantum experiment 108 N nf parameter 110 ni parameter 109 nitrogen contact with body 9 nitrogen gas flowmeters caution 11 NOESY pulse sequence 82 nonintegral spin quadrupolar nuclei 14 non narrowed spectra 95 notational conventions 12 noxious samples 19 np parameter 101 102 104 105 107 nuclear magnetic dipole 14 nuclei 95 VNMR 6 1C User Guide Solid State NUR 114 Index nutate macro 111 NUTATE pulse sequence 111 nutation experiment 111 O observe linear modulator setting 64 magnetization 66 nucleus pulse calibration 65 power setting 64 receiver board 35 refocusing pulse 87 selective inversion pulse 85 transmitter board 38 OFF button 38 off resonance decoupling in solids 29 Opella and Fry 29 open loop O mode 54 Operate button 37 organic solids 14 P pl parameter 62 85 90 96 105 106 p180 parameter 65 96 p2 parameter 27 60 62 67 80 p3 parameter 30 61 62 pacemaker warning 8 Pake doublet 97 passl macro 79 PASS1 pulse sequence 78 PC compatible computer 54 pcrho parameter 65 pdp parameter 29 61 62 65 pedestals 99 periods parameter 86 phase glitch 101 removal 47 phase parameter 66 70 82 98 phase shift errors 102 phasel parameter 101 102 phase2 parameter 46 47 101 102 phase sensitive spectrum 68 pMMA end caps 18 pneumatics tachometer box 16 54 description 50 variable temperature version 50 polarization transfe
171. tization occurs The optimum p2 can lie anywhere from 100 to 5000 us Generally the optimum value is similar for a class of compounds but for new types of samples an optimization of p2 is highly desirable Figure 7 shows a typical optimization Note that a simultaneous optimum for all carbons in a spectrum does not necessarily occur Generally a value of 1000 us is adequate for normal crystalline solids and 3000 us for soft solids PF Figure 7 Array of Contact Times Optimizing the Repetition Rate Acquisition times in CP MAS spectra are determined by the desired spectral resolution Typically set sw 300p or sw 300 sfrq With at 0 064 this gives at least 2048 data points and a digital resolution of 4 Hz a reasonable value The repetition rate is consequently determined by the parameter d1 the delay between pulses CP MAS spectra are acquired with 90 observe pulses In this case the optimum repetition rate is 1 25 7 For cross polarization spectra this T is the T of the protons for gated decoupling spectra it is the T of the carbon or other nucleus These T values can vary widely as in liquids At 300 MHz a d1 of 5 seconds is usually acceptable for polymers at 400 MHz 10 seconds is better Suppressing Spinning Sidebands NMR spectra of solids at high magnetic fields often have significant spinning sidebands While these sidebands contain information about the chemical shift anisotropy they can complicate the interpreta
172. ton Wideline Separation WISE correlates the CP MAS spectrum of the observe nucleus with the proton wideline spectrum due to H H and X H interactions An optional mixing period provides an exchange experiment that mixes wideline patterns due to proton spin diffusion The method was first presented by Zumbulyadis for the study of amorphous silicon semiconductors The method was extended to polymers and Schmidt Rohr et al added a mixing period was WISE is useful for the characterization of polymers with complex morphology that includes hard and soft domains Domains are distinguished by the wideline spectrum broad 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 70 Chapter 6 Solid State NMR Experiments if rigid and narrow if motionally averaged Corresponding observe chemical shifts indicate the segmental composition of the regions With a spin diffusion mixing period WISE1 additionally determines proximity of the domains in space WISE also provides the means to obtain the proton wideline spectrum a UNITYplus system with only a standard digitizer For WISE1 sw1 can be set in excess of 100 kHz The macro wisel converts a parameter set obtained with XPOLAR or XPOLARI for the WISE experiment Power levels and proton 90 pulse width are retained Default parameters set up for WISE with no mix period and a 200 kHz spectral width Applicability WISE1 is available for UNITYplus and UN TYINOVA systems and can be found in SolidsL
173. ules 1977 10 384 Spinning Sidebands Herzfeld J Berger A E J Chem Phys 1980 73 6021 Dixon W T J Magn Reson 1981 44 220 Dixon W T J Magn Reson 1982 49 341 Dixon W T J Magn Reson 1985 64 332 Protonated Carbon Suppression Opella S J Fry M H J Am Chem Soc 1979 101 5856 Frye J Maciel G E Magical Angle Adjustment with KBr J Magn Res 1980 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 32 Chapter 2 CP MAS Solids Operation 2 13 Useful Conversions Convert from 90 pulse width to yH 8 250 YH KH2 oospuisewidtn 9 Convert from field strength in gauss to field strength in gauss lH YH kHz 4 3 YH gauss Fe YH kHz YH gauss Convert from rf fields to power levels P watts yH 33 VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 Chapter 3 Wideline Solids Module Operation Sections in this chapter e 3 1 Wideline Solids Module this page e 3 2 Wideline Experiments page 38 e 3 3 SSECHO Pulse Sequence page 39 e 3 4 Data Acquisition page 39 e 3 5 Standard Wideline Samples page 41 e 3 6 Data Processing page 43 Unnarrowed spectra of solid samples can often reveal a great amount of information In wideline NMR no attempt is made to narrow the resonances as done by CP MAS and patterns up to 0 5 MHz or wider can occur As lineshape is of the utmost importance the spectrometer mu
174. ure 38 Figure 39 Figure 40 Rotating Frame Spin Lattice Relaxation Measurements Sequence ou eee Pulse Sequence for Measuring H Dj eek E E ieaetiiaee nent egieee bles Solids Cabinet Layout Open Front View 0 ce eescsseeseceeeeseceeceseeeeeeeeseeeeseeeaeesaeeaes High Power Amplifiers Status Panel 0 0 cc eeeseeesecsseseeseeeceeeseesessecaeeeesaceaeeeeeeeeaee Real Channel FID aptent scsuscssisit isdheussestdeseusissncvesssendelussadbeatseohdesssebestheuenoevenbvanveces FLIPFLIP FID at Exact 90 Pulse oo cee eceesceecseeeeeececeeeseeseceecseesesaecaeeeesaceaeeeseeeeaees FLIPELOP Trani Tracks wisssiateiscetcdess sed bie aan ani ane Sisees PUIPPLOP Desired FID instroom nnn E E pudeseoubees Pneumatics Tachometer Box for CP MAS Probes AA Different Modes of the Rotor Synchronization ACCeSSOory seseeeeeeeereeerereerrrerersree Base of a Varian High Speed Spinning Rotor sssesssseseeseseerssrrrrsreresreeserrererresenrnsenrns Doty Double Bearing Rotor oo eee ceee cee ceseeseceseeseceeceeceeeeseseeeeeeseneeseesaeesaecaeesaeaes TOSS P ls SEQUENCE scs ecasccsesewsssecavesuacsers se sccusstiupinascdostssepeutvosesegesedeecuscencessodazeceasarees Protonated Carbon Suppression Sequence 0 0 eee ee ee eeeceeeeeceeeeeeeeeeeeeeeseesaecseesaeaes Rotating Frame Spin Lattice Relaxation Measurements Sequence eee Pulse Sequence for Measuring H Ti Sreo a A EESE XPOLART EE XPWXCAL E D XNOESYSYNC Pulse Sequence oo eee eeeseeeeecseecs
175. ution occurs symmetrically about the refocusing pulses with two mrev 8 cycles per f dwell Phase shifts are less severe but the maximum sw1 is smaller refocus set to n provides the simplest DIPSHIFT1 pulse sequence allowing the largest value of sw1 Refocusing pulses are not used phase correction must be performed in f The parameter sense is hidden when refocus is set to n sense is setto r or See refocus above Reference Munowitz M G Griffin R Oo Bodenhausen G Huang T H J Am Chem Soc 1981 103 2529 6 19 SEDRA2 Simple Excitation of Dephasing Rotational 87 Echo Amplitudes In the last few years there has been much interest in the measurement of the homonuclear Be dipolar interaction for measurement of internuclear distance in solids Unfortunately the magic angle spinning required to obtain a high resolution spectrum also averages the dipolar interaction to zero Therefore special methods are needed to obtain the e connectivity information SEDRA Simple Excitation of Dephasing of Rotational Echo Amplitudes is one of the new experiments created for this purpose Figure 39 is a diagram of SEDRA SEDRA is applied after cross polarization and consists of a train of 7 pulses synchronized with the middle of each rotor period Acquisition follows at the next rotor period and proton decoupling is maintained throughout SEDRA pulses reintroduce the dipolar interaction and cause a diminution of the
176. wing page 103 6 31 BR24 Cycled BR24 Miultiple Pulse Line Narrowing page 104 01 999162 00 A0800 VNMR 6 1C User Guide Solid State NUR 58 Chapter 6 Solid State NMR Experiments e 6 32 CORY24 Cycled CORY24 Multiple Pulse Line Narrowing page 105 e 6 33 MREVCS Multiple Pulse Chemical Shift Selective Spin Diffusion page 107 e 6 34 MQ SOLIDS Multiple Quantum Solids page 108 e 6 35 SPINDIFF Spin Diffusion in Solids page 109 e 6 36 FASTACQ Multinuclear Fast Acquisition page 110 e 6 37 NUTATE Solids 2D Nutation page 111 This chapter describes CP MAS triple resonance wideline and multipulse pulse sequences for solid state NMR To aid in identification the names of pulse sequences are given in all capital letters In general most of these experiments are intended for UNITYINOVA and UNITYplus systems Running these sequences on UNITY and VXR S systems may require some modifications None of these sequences are available on MERCURY and GEMINI 2000 systems The macros for some of the solid state NMR sequences are located in maclib The macros for other solid state NMR sequences are located in the user library userlib User Library Terms and Conditions Material submitted to the user library is distributed by Varian as a service to its users All rights to the material submitted are retained by the submitter unless explicitly surrendered in the accompanying README documen
177. xchange can occur via the spinning sidebands unless the mixing time is synchronized to the rotor period When this is done cross peaks appear when self or chemical exchange occurs Figure 27 is a diagram of the sequence d2 pw 90 p2 p2 cp90 cp90 13C Rotor D D D O S D B B S TTT tT ttt te tt et tt Figure 27 XNOESYSYNC Pulse Sequence Macro The xnoesysync macro sets up parameters for the XNOESYSYNC pulse sequence Parameters pw is the H 90 pulse in microseconds for cross polarization p2 is the contact time in microseconds d2 is the evolution time in seconds dmis set to nny for no proton decoupling during the mixing time or dmis setto nyy for proton decoupling during the mixing time Level controls decoupler power during cross polarization level1f controls fine decoupler power during cross polarization level2 controls decoupler power during acquisition level2f controls fine decoupler power during acquisition time phase is 0 for P type phase is 1 for N type or phase is 1 2 for phase sensitive The Veeman experiment requires phase 0 cp 90 is the 3C 90 pulse in microseconds mix is the mixing time in seconds sync is set to y to run rotor with sync sync is set to n to run unsynchronized normal NOESY VNMR 6 1C User Guide Solid State NMR 01 999162 00 A0800 6 5 MASEXCH1 Phase Sensitive Rotor Sync Sequence for Exchange Technique The minimum phase cycle is 16 transients and the full

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