Comparative study of the semiempirical three-parameter potential energy functions for diatomic molecules

Abstract

A comparative study is made of four three-parameter semiempirical potential energy functions for 32 electronic states of diatomic molecules and their ions:n2:X1gS g + ,B3πg,A3 gSu,C3u,B′3 gSu.a1 πg, a′gS u − ,Ω1δuN 2 + :X2 gS g gS +A2 π,C2 gS u + ,B2 gS u + CO:X1gS+,a3 π, a′3 gSu,e3 gS−,d3gD1,A1π CO+:X2gS+,A2 π,B2gS+ O2:X3gS g − ,B3 gSu,c1 gS u − ,b1gS g s ,a1 δg,c3 δu O 2 + :X2πg,A2 πg, a1 πg,b4 gS g − A program for numerically integrating the radial Schrodinger equation by the Cooley method is worked out. Certain additional units are introduced to conserve computer time. The resulting vibrational levels are compared with the experimental levels for all the electronic states studied. It is concluded on the basis of this analysis that it is not possible to describe equally well all the electronic states of various molecules on the basis of any single three-parameter potential function. A method for choosing a potential function for describing some particular electronic state of a diatomic molecule is proposed.