“Multiple-scattering” (green's function) model for polyatomic molecules II. Theory

Abstract

A “multiple-scattering” or Green's function technique for calculating bound one-electron molecular eigenstates has been proposed in a previous paper. The original formulation of this technique is designed primarily for the treatment of the spectral characteristics of complex polyatomic molecules, where more conventional molecular-orbital methods are difficult to apply. In the present paper, the theory is modified in order to allow a more accurate treatment of symmetric polyatomic molecules and molecular ions. The modification consists of taking into account the long-range nature of the molecular potential and the “mixing” of a single-center partial-wave expansion of the one-electron wave function with the original multicenter partial-wave expansion. This is achieved without sacrificing the basic computational simplicity of the method, in particular, the separation of the “atomic” and “structural” aspects of the secular problem and the absence of multicenter integrals.