Van der Waals Coefficients for the Alkali Halides from Optical Data

Abstract

The van der Waals coefficients that arise from the dipole—dipole interaction of ions in the alkali halides are discussed and computed for the negative—negative, positive—positive, and negative—positive interactions of the 20 salts. Also the polarizabilities of the negative ions and the optical strength per ion are computed. The computation was mainly based on data of the absorption coefficient for frequencies corresponding up to 11.4 eV published by Eby et al. The van der Waals coefficients are compared with those of Mayer (1933) and the polarizabilities with the values given by Ruffa (1962), Tessman et al. (1953), and Pauling (1927); agreement was found to be satisfactory for both sets of values.