Varian Solid-State NMR - MREVCS-Multiple Pulse Chemical-Shift Selective Spin Diffusion; Figure 56. MREVCS Pulse Sequence

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
Figure 56 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