6.27 MREVCS—Multiple Pulse Chemical-Shift Selective Spin Diffusion
01-999162-00 C0402
VNMR 6.1C User Guide: Solid-State NMR
122
Reference
Haubenreisser, U.; Schnabel, B. J. Magn. Reson. 1979, 35, 175.
6.27 MREVCS—Multiple Pulse Chemical-Shift Selective
Spin Diffusion
shows the diagram of a novel experiment, called MREVCS, developed by Spiess
and coworkers, that involves a multiple-pulse selection of
1
H magnetization based on
chemical shift differences during the mixing time,
1
H spin diffusion during a mixing time,
and high-resolution
13
C CP/MAS detection to study the mixing of components on a
molecular scale. This version is for
1
H detection.
Macro
The macro
mrevcs
retrieves a parameter set suitable for the MREVCS experiment.
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
1
H spin diffusion.
cycles
is the number of times through the multiple pulse cycle.
cycles
and
tof
, in combination, determine the chemical shift.
Figure 56. MREVCS Pulse Sequence
Tx
d1 dtau
pw
dtau
pw
tau+dtau
pw
dtau
pw
tau+dtau
pw
dtau
pw
tau+dtau
pw
dtau
pw
tau
stau
pw
dtau
pw
dtau
pw
tau+dtau
pw
dtau
pw
tau+dtau-2.0e-7
pw
dtau
pw
tau+dtau
pw
dtau
pw
tau
A
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
1.0s
0.
8u
0.
8u
4.
3u
0.
8u
4.
3u
0.
8u
4.
3u
0.
8u
3.
5u
94.
8u
0.
8u
0.
8u
4.
3u
0.
8u
4.
1u
0.
8u
4.
3u
0.
8u
3.
5u