Programs in Physics & Physical Chemistry
|[Licence| Download | New Version Template] abvg_v1_0.gz(10 Kbytes)|
|Manuscript Title: Simulation of EPR-spectra of randomly oriented samples. See erratum Comp. Phys. Commun. 28(1982)217.|
|Authors: C. Daul, C.W. Schlapfer, B. Mohos, J. Ammeter, E. Gamp|
|Program title: POWDER|
|Catalogue identifier: ABVG_v1_0|
Distribution format: gz
|Journal reference: Comput. Phys. Commun. 21(1981)385|
|Programming language: Fortran.|
|Computer: CDC 6000.|
|Operating system: SCOPE 3.4.|
|RAM: 130K words|
|Word size: 8|
|Peripherals: disc, graph plotter.|
|Keywords: Crystallography, Anisotropic g-tensor, Anisotropic hyperfine Tensor, Anisotropic Perturbation calculation, Numerical integration And differentiation, Noise filter, Epr.|
Nature of problem:
The EPR spectra of polycrystalline paramagnetic samples exhibits often complex features due to hyperfine and/or dipole-dipole and/or quadrupole interaction of the electronic and nuclear spins. This program calculates the first derivative of the EPR absorption spectrum of randomly oriented samples using the following approximations: i) the eigenvalues of the spin Hamiltonian are given by second order perturbation theory; ii) theintensities of the EPR transitions are determined by Zeeman interaction only; iii) the paramagnetic species are uniformly or randomly distributed in space. iv) 'allowed' transactions are calculated only.
The single crystal spectra for particular orientations are calculated. They are summed over all spacial orientations (Simpson rule) and convoluted with a line shape function giving the absorption line. A subsequent numerical derivation yields the 1st derivative spectrum and reduces the random derivations due to the limited number of orientations.
In the present version, the stick spectrum is convoluted with a line- shape function after the summation over all orientations has been carried out. This implies that only line widths independent upon orientation and mI can be treated. Furthermore, since a perturbation calculation is used, it is required that Eta(Zeeman) > Eta(hyperfine), Eta(Zeeman) > Eta(dipole-dipole) and that Eta(hyperfine) > Eta(quadrupole).
Ranges between 10 s and 10 min on the CDC 6000.
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