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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 Phys., 44, 2719 (1966) or Baugher, Taylor, Oja, and Bray (unpublished Brown University Report)].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). |