Lattice Dynamics of Sodium Halides

Abstract

A modified shell model developed earlier by the authors which included the effect of three-body forces has been used to study the lattice dynamics of sodium halides. The model has been ascribed a fundamental basis by pointing out that amongst the current phenomenological models, this one makes the nearest approach to the shell model recently derived by Sinha on rigorous quantum-mechanical considerations. Excellent agreement has been obtained with experimental data on phonon dispersion relations, specific heats at constant volume, and the infrared absorption and Raman scattering spectra of the solids.