Electronic polarizability of ions in the alkali-halide crystals

Abstract

A theoretical estimate of the high-frequency dielectric constants is made using the molar polarizabilities for a number of alkali halides. These are shown to be in good agreement with the new and more reliable experimental data. Analysis by means of the additivity rule within the family of salts is used to compute the total free ion polarizability of ionic constituents and the change in polarizability when the ions are placed in a crystalline environment. Furthermore, the anion electronic polarizability in ionic crystals has been determined. It is found to vary from crystal to crystal, as opposed to the generally accepted assumption that each ion has the same polarizability in all compounds. The dependence of polarizability upon ionic radii has been discussed. The results from this simple analysis compare well with other determinations.