Bruker BioSpin Solid State NMR - Dumbo

Decoupling Techniques
User Manual Version 002 BRUKER BIOSPIN 97 (327)
Vinogradov et. al. have published shapes with much fewer steps and different
phases. The pulse length for the shape does not depend on the number of steps,
but only on the applied RF-field. Using the include file lgcalc.incl, a pulse p5 is cal
-
culated from cnst20=RF-field in Hz. The total shape pulse length must be 2*p5.
To use pmlg decoupling, save the pulse program fqlg under a different filename
and change calculations and loop as follows:
define loop counter count; calculate number of LG periods according to aq
"count=aq/(2*p5)"
define pulse pmlg
"pmlg=2*p5"
"sp1=pl13" set shape power to pl13 for LG (TS2.1 only)
.
3 (pmlg:sp1 ph3): f2 for one full PMLG unit, as for lgs-1 shape
lo to 3 times count
References:
1. A. Bielecki, A.C. Kolbert, and M.H. Levitt, Frequency-Switched Pulse Sequences: Homonuclear De-
coupling and Dilute Spin NMR in Solids, Chem. Phys. Lett. 155, 341-346 (1989).
2. A. Bielecki, A.C. Kolbert, H.J.M. deGroot, R.G. Griffin, and M.H. Levitt, Frequency-Switched Lee-Gold-
burg Sequences in Solids, Advances in Magnetic Resonance 14, 111-124 (1990).
3. E. Vinogradov, P.K. Madhu, and S. Vega, High-resolution proton solid-state NMR spectroscopy by
phase modulated Lee-Goldburg experiments, Chem. Phys. Lett. 314, 443-450 (1999) and references
cited therein.
DUMBO
DUMBO (Decoupling Uses Mind Boggling Optimization) is a phase modulation
scheme where the phase modulation is described in terms of a Fourier series
The shape can be created using the AU-program DUMBO. The DUMBO shape
file in the release version of TOPSPIN is calculated for 32 µs pulses. To create
your own DUMBO shape you can also use the au-program dumbo. See instruc
-
tions in the header of the au-program for proper use.
The above pulse program to observe J-couplings with DUMBO decoupling would
be written as follows:
define loop counter count;calculate number of LG periods according to aq
"count=aq/(p10)"
.
3 (p10:sp1 ph3):f2 ;p10 set by AU-program DUMBO (n*32 µsec)
lo to 3 times count