Evaluation of Van der Waals dipole-dipole and dipole-quadrupole energies in alkali halides

Abstract

In this paper we have estimated the Van der Waals dipole-dipole and dipole-quadrupole energies in alkali halides. The calculations are based on the theory of electronic polarizabilities proposed by Ruffa. The magnitudes of Van der Waals energies in alkali halides are found to be larger by a factor of 2 to 4 than those reported by earlier investigators. The reasons for the differences between results of other investigators and the current work have been discussed with special emphasis on electronic polarizabilities of ions. It is pointed out that the larger magnitudes of the Van der Waals energies obtained in the present paper are in conformity with the studies on phase transition and lattice-dynamical behavior of alkali halides.