Brief Comments on Perturbation Theory of a Nonsymmetric Matrix: The GF Matrix

摘要

Perturbation theory for nonsymmetric matrices is discussed for the GF matrix for molecular vibrations. As a simple extension of early results, two approaches are given: one a direct diagonaliztion of the nonsymmetric matrix, the other a presymmetrization. Presymmetrization of the GF matrix, well knwon for #DELTA#F, is also described here for #DELTA#G. It permits the use of standard perturbation theory for symmetric matrices. Application of the second-order expression for the #DELTA#G case to the frequencies of many ozone isotopomers is given elsewhere.