The Stochastic Hyperfine Interactions Modeling Library

Abstract

The stochastic hyperfine interactions modeling library (SHIML) provides a set of routines to assist in the development and application of stochastic models of hyperfine interactions. The library provides routines written in the C programming language that (1) read a text description of a model for fluctuating hyperfine fields, (2) set up the Blume matrix, upon which the evolution operator of the system depends, and (3) solve the eigenvalues and eigenvectors of the Blume matrix so that theoretical spectra of experimental techniques that measure hyperfine interactions can be calculated. The optimized vector and matrix operations of the BLAS and LAPACK libraries are utilized; however, there was a need to develop supplementary code to find an orthonormal set of (left and right) eigenvectors of complex, non-Hermitian matrices when degeneracy is present. In addition, example code is provided to illustrate the use of SHIML to generate perturbed angular correlation spectra for the special case of polycrystalline samples in cases for which terms higher than A22 can be neglected.

Authors

Matthew O. Zacate
Dept. of Physics and Geology
Northern Kentucky University

William E. Evenson
College of Science and Health
Utah Valley University

Software requirements

The code is written in the C programming language; therefore, a C compiler is needed. The code also requires that the following packages be installed:

Licensing

SHIML is copyrighted by Matthew O. Zacate and William E. Evenson and will be distributed under the GNU General Public License (version 3) with an additional citation condition.  It has been published in Computer Physics Communications  (vol. 182, pp. 1061-1077, 2011 [42])  and can be found on-line here.  The full documentation and code is available at the Computer Physics Communications Program Library.

Acknowledgements

This work is funded in part by NSF grant DMR 06-06006 (Metals Program). Additional computational resources were obtained with funding from KY EPSCoR grant RSF 012-03. We would like to thank Jeffery Hodges, Phil Matheson, Carlos Moreno, Harun Muhammed, Tyler Park, and Michael Stufflebeam for testing the code and providing helpful suggestions for its improvement.
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Department of Physics and Geology
Northern Kentucky University
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