Original scientific paper

An Iterative Perturbation Theory-Based Algorithm for Calculation of Diagonal Force Constants of the ν₃ Modes in Quasi-Tetrahedral Systems with Low Anharmonicity

Ljupčo Pejov ; Institute of Chemistry, Arhimedova 5, P.O.B. 162, 91000 Skopje, Macedonia
Vladimir M. Petruševski ; Institute of Chemistry, Arhimedova 5, P.O.B. 162, 91000 Skopje, Macedonia

Abstract

A novel, stationary perturbation theory – based iterative algorithm for calculation of the diagonal force constants of the ν₃ modes in tetrahedral and quasi-tetrahedral systems with low anharmonicity is developed. The diagonal elements in the potential energy expression are calculated on the basis of experimentally measured fundamental and second-order transition wavenumbers, in a self-consistent manner. Perturbation corrections up to the second order are included in the model. The procedure is rapidly convergent, simple, and may be easily implemented within computer programs. The calculated diagonal force constants are consistent with the measured fundamental and second-order transition wavenumbers. The proposed model is applied to several isomorphously isolated (distorted-tetrahedral) sulfate impurities in selenate and chromate matrices. Experimental data for these systems were obtained by FT-IR spectroscopy.

Keywords

Quasi-tetrahedral molecules; diagonal force constants – calculation of; Perturbation theory; anharmonic oscillator; sulfate impurities; isomorphous isolation

Hrčak ID:

132310

URI

https://hrcak.srce.hr/132310

Publication date:

1.12.1999.

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