THIS INFORMATION IS OBSOLETE AND IS PROVIDED ONLY FOR ITS HISTORICAL VALUE

After H. S. Story and D. Kline, Department of Physics, SUNY, Albany, New York 12246 (QCPE 154), with acknowledgment to E. Rybacewski

The program VMASS is a modification of the program POWPAT (QCPE 154) with simulation of MAS and VAS NMR spectra in addition to the static spectra simulated by the original program. Since magic angle sample spinning (MAS) is becoming common for quadrupolar nuclei and variable angle sample spinning (VAS) is available on a number of spectrometers, this simulation program should be useful to a number of experimenters. The detailed documentation is included in the source code.

The POWPAT program computes and plots powder patterns andspectra 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 Phys., 44, 2719 (1966) or Baugher, Taylor, Oja and Bray (unpublished Brown University Report). The quadrupolar and chemical shift terms are treated as perturbation on the Zeeman term and are correct through second order 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 space. The frequencies are then computed and a density function or powder pattern constructed. The powder pattern is then convoluted with a Gaussian (or Gaussian derivative) to produce a spectrum simulating that obtained from a wide-lined spectrometer (derivative mode). This program assumes that all transitions have the same linewidth.

FORTRAN 77 (PROFORT and Microsoft 4.0) Lines of Code: 465