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Manuscript Title: Simulation of powder EPR spectra with axial symmetry.
Authors: R.S. de Biasi, J.A.M. Mendonca
Program title: SIMULAPO
Catalogue identifier: AAOF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 28(1982)69
Programming language: Fortran.
Computer: B 6800.
Operating system: WFL.
RAM: 25K words
Word size: 52
Keywords: Crystallography, Epr, Axial d-tensor, Powder spectrum.
Classification: 8.

Nature of problem:
The determination of the spin Hamiltonian parameters from powder spectra often requires a full simulation of the spectrum, especially when the zero-field parameters are of the same order as the Zeeman term. This program calculates the first derivative of the EPR absorption spectrum of powder samples using the following approximations: i) the paramagnetic species is randomly distributed in space; ii) the linewidth is isotropic and is the same for all transitions.

Solution method:
The single crystal spectra are calculated exactly for a large number of orientations (typically 90) of the magnetic field. These spectra are convoluted with a first-derivative line shape function and added to yield the powder spectrum.

In its present version, the program is restricted to spectra with axial symmetry (E=0), no hyperfine terms (A=0) and isotropic g. The electron spin S must be in the range 1<=S<=5/2.

Running time:
The running time on the B 6800 is of the order of 30S(2S+1) seconds, where S is the electron spin. It thus ranges from 90 s (for S=1) to about 8 min (for S=5/2).