Electronic polarizabilities, ionic radii, and repulsive potential parameters for diatomic alkali halide molecules

Abstract

The electronic polarizabilities of ions in diatomic alkali halide molecules calculated using the Seitz–Ruffa energy level analysis are found to agree closely with those recently estimated by Brumer and Karplus utilizing the exchange perturbation theory. A sensible test of these polarizabilities has been presented by calculating the molecular properties like dipole moments. Ionic radii for alkali and halogen ions appropriate to diatomic molecules are determined using the relation between size and effective nuclear charges. The radii thus evaluated are found to be nearly additive and reproduce the internuclear distances within about ± 0.10 Å for all the alkali halide molecules except for RbF and CsF. An analysis of interaction energies in alkali halide molecules is presented by adopting two potential forms for the repulsive energy showing, respectively, the inverse power dependence and exponential dependence on internuclear distance. The additivity of repulsive potential parameters is discussed in the light of recent investigations. The results for the molecular constants obtained from the exponential form are in much better agreement with experiment than those estimated from the inverse power form.