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154. POWPAT: Powder Patterns and Spectra for NMR
Transitions
by H. S. Story and D. Kline, Department of Physics,
SUNY at Albany, Albany, New York 12246, with
acknowledgement to E. Rybacewski
Program POWPAT computes and plots powder patterns and
spectra corresponding to nuclear magnetic resonance
transitions which result from the spin Hamiltonian with
nuclear Zeeman quadrupole and chemical shift terms
[see, for example, Narita, Umeda, and Kusumoto, J.
Chem. Phys., 44, 2719 (1966) or Baugher, Taylor, Oja,
and Bray (unpublished Brown University Report)]. Terms
are treated as perturbations on the Zeeman term and are
correct through second and first order respectively.
The powder pattern is simulated by setting the crystal
at a large number of angles, theta and phi, on a
regular grid in cosine theta and phi space. The
frequencies are then computed and a density function or
powder pattern constructed. The powder pattern is then
convoluted with a Gaussian derivative to produce a
spectrum simulating that obtained from a wide-line
spectrometer (derivative mode). The output of this
program is in the form of plots of the powder patterns
and convoluted spectra. The corresponding frequencies
and amplitudes are printed.
NOTE: If the powder pattern extends beyond the range
of PMIN or PMAX, the resulting step will produce a
response in the convoluted spectrum; thus, peaks
at the ends of the spectra are to be disregarded.
FORTRAN IV
Lines of Code: 387
Recommended Citation: H. S. Story and D. Kline, QCPE
11, 154 (1970).
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