Harmonic force fields from scaled SCF calculations: Program ASYM40

Hedberg, L. and Mills, I. (2000) Harmonic force fields from scaled SCF calculations: Program ASYM40. Journal of Molecular Spectroscopy, 203 (1). pp. 82-95. ISSN 0022-2852 doi: 10.1006/jmsp.2000.8168

Abstract/Summary

We report an extended version of our normal coordinate program ASYM40, which may be used to transform Cartesian force constants from ab initio calculations to a force field in nonredundant internal (symmetry) coordinates. When experimental data are available, scale factors for the theoretical force field may then be optimized by least-squares refinement. The alternative of refining an empirical force field to fit a wide variety of data, as with the previous version ASYM20, has been retained. We compare the results of least-squares refinement of the full harmonic force field with least-squares refinement of only the scale factors for an SCF calculated force field and conclude that the latter approach may be useful for large molecules where more sophisticated calculations are impractical. The refinement of scale factors for a theoretical force field is also useful when there are only limited spectroscopic data. The program will accept ab initio calculated force fields from any program that presents Cartesian force constants as output. The program is available through Quantum Chemistry Program Exchange.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/7298
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy
Publisher	Academic Press
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