Application of potential constants: Molecular chemical potential changes on formation of heteronuclear diatomic molecules—VI

Abstract

The harmonic and anharmonic potential (force) constants of heteronuclear diatomic molecules, which are usually available from normal coordinate analyses, are applied to problems of determining the molecular chemical potential changes on formation of such molecules. The approach developed here is mainly based on density—functional theory, that is, the respective atomic energies in a molecule are expanded with the numbers of electrons and the nuclear potentials. These expansions are allowable because the ground-state energy for a system of N electrons and given nuclear potential ν( r) is a functional of N and ν( r). To test the reliability of the approach, we have calculated the molecular chemical potentials of alkali halides and other heteronuclear diatomic molecules, and their results have been compared favorably with the data obtained from Sanderson's Principle and the ab initio SCF calculation. We have also estimated apparent chemical hardnesses as well as integral terms including Fukui functions that provide good measures for electron transfers between atoms on molecule formation. Brief discussions on the molecular chemical potential changes are given.