2.9 XPOLAR1—Cross-Polarization
01-999162-00 C0402 VNMR 6.1C User Guide: Solid-State NMR
40
• tpwrm is the observe linear modulator setting .
The parameter tpwrm is linearly proportional to the applied transmitter voltage—
doubling tpwrm halves the value of the pulse width.
• dpwr is the decoupler power setting for decoupling throughout the acquisition period .
• cppwr (UNITY only) is the decoupler power setting for cross polarization when
dblvl2=’y’.
• dipolr is the decoupler linear modulator setting during acquisition (0 minimum
voltage to 4095 for INOVA or 255 for MERCURY series maximum voltage). The value
of dipolr is linearly proportional to the applied decoupler voltage—doubling
dipolr doubles the decoupler field strength (in kHz).
• dblvl2 (UNITY only) is set to ‘y’ to obtain the parameter cppwr.
• crossp is the decoupler linear modulator setting during cross-polarization and the
initial 90
° pulse (0 minimum voltage to 4095 for INOVA or 255 for MERCURY series
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.
• 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.
• pcrho greater than 0.0 implements an additional observe pulse following the contact
time. Use pcrho for observe T
1ρ
measurements. The units for pcrho are
microseconds.
• dm should be set to 'nny'. The decoupler has a maximum duty cycle of 20%.
• pdp set to 'y' implements interrupted decoupling for a period pdpd2 to cause
suppression of protonated carbons.
• pdpd2 is set greater then 0.0 (see pdp), pdpd2 is in microseconds
• d2 is set greater than 0.0 (see p180), d2 is in seconds.
• srate is the sample spinning speed, in Hz.
• hsrotor set to ‘y’ allows automatic update of the value of srate if automatic
spinning speed control is used.
• 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 correctly because delays
are calculated from 1.0/srate.
Spectrometer Minimum Maximum
INOVAcpmas 0 4095
MERCURYcpmas 0 255
Spectrometer Minimum, dB Maximum, dB
INOVAcpmas -16 63
MERCURYcpmas 063
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