Chapter 6. Solid-State NMR Experiments
95
VNMR 6.1C User Guide: Solid-State NMR
01-999162-00 C0402
fslg2.DEC
provides phase continuous frequency switched Lee-Goldberg decoupling.
This pattern decouples protons from themselves, but leaves a residual
13
C–
1
H 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
XPOLXMOD1 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
high spinning 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.
is a diagram of the sequence.
Applicability
XPOLXMOD1 and XPOLHMOD1 are available on UNITYplus and
UNITY
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 XPOLAR1 for these experiments Power levels and pulse widths are retained.
Figure 38. XPOLXMOD1 Pulse Sequence
cntct
cntct
(tpwrm)
(crossp)
(dipolr)
Tx
Dec
at
d1
A
C
xpolxmod1
"pattern"
xpolhmod1
"pattern"
pw
xpolhmod1
(pwpuls)