6.2 XPOLAR1—Cross-Polarization
01-999162-00 C0402 VNMR 6.1C User Guide: Solid-State NMR
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Cross-polarization amplitudes should be controlled using the fine attenuator. The fine
attenuator has a range of 60 dB for Inova and 48 dB for MERCURY systems down from the
course attenuator. The coarse attenuator is set to a value corresponding to the maximum
specification of the probe. Cross-polarization on the UNITY requires the use of both the
coarse and fine attenuators (6 db range).
Applicability
XPOLAR1 can be found in /vnmr/psglib. The MERCURYplus and MERCURY-VX
version of XPOLAR1 is not interchangeable with XPOLAR1 for
UNITY
INOVA and
UNITYplus systems. UNITY systems can use both XPOLAR1 and XPOLAR by setting
dblvl2=’y’.
Macro
When this macro is run on a
UNITY
INOVA, UNITYplus, and UNITY, 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 XPOLAR1 are removed. On MERCURY-VX or MERCURYplus the
macro XPOLAR1 will convert parameters contained in experiments run on
UNITY
INOVA,
UNITYplus, and UNITY when these data sets are loaded on the system and the macro is
run.
For users familiar with
UNITY
INOVA, UNITYplus, and UNITY solids, note the
following:
• If the UNITY power parameters are defined (in an XPOLAR parameter set),
they are converted to the corresponding
UNITY
INOVA and UNITYplus
parameters: (level1=cppwr level2=dpwr level1f=crossp
level2f=dipolr p2=cntct tpwrf=tpwrm) and dblvl2 is set to 'n'.
If dblvl2=’y’, both cppwr and dpwr are used. If dblvl2=’n’, cppwr is not used
and dpwr=cppwr.
• xpolar1 does not convert an arbitrary parameter set for solids. First retrieve a
solids parameter set (e.g., xpolar.par in the VNMR directory parlib) and
then convert it with the xpolar1 macro.
Parameters
• xpol is set to 'n' for direct polarization or xpol is set to 'y' for cross-polarization.
• pw is the observe pulse for direct polarization, or the proton 90
° pulse for cross-
polarization. pw is in microseconds.
• pwx is the observe 90
o
pulse, used for TOSS and dipolar dephasing, pwx is in
microseconds.
• cntct is the cross-polarization contact time, in microseconds.
• tpwr is the observe power setting .
Spectrometer Minimum, dB Maximum, dB
INOVAcpmas -16 63
MERCURYcpmas 063
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