Chapter 6. Solid-State NMR Experiments
99
VNMR 6.1C User Guide: Solid-State NMR
01-999162-00 C0402
Parameters
XPOLEDIT1 makes use of the
UNITY
INOVA and UNITYplus parameters
tpwr
,
tpwrm
,
dpwr
,
cppwr
,
dipolr
,
crossp
,
dblvl2
,
pw
and
cntct
. See
for a
description of these parameters.
p3
is the depolarization time, in microseconds. The phase of the proton channel is reversed.
p4
is the repolarization time, in microseconds.
References
Sangil, R.; Bildsoe, H.; Jacobsen, H. J. J. Magn. Reson. 1994, 107 (Series A), 67.
6.12 3QMAS1—Triple-Quantum 2D for Quadrupole Nuclei
3QMAS1 is a two-pulse, two-dimensional experiment for the detection of isotropic spectra
of quadrupole nuclei (I=n/2, n/2>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.
is a diagram of the 3QMAS1 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 available for all UNITY systems and can be found in the
userlib
. The
default parameters of the setup macro are applicable for only
UNITY
INOVA and UNITYplus.
The processing parameter
daslp
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
Figure 41. 3QMAS1 Pulse Sequence
pws
A
C
at
periods/srate
pw3q
pw3q
d1
d2
tau
(tpwrms)