A New Model for the Lattice Dynamics of Alkali Halides

Abstract

Qualitative properties of the electronic band structure of a KCl crystal are used to derive a simple two-parameter model for the correlation function c(q, q') which arises in the theory of lattice dynamics. This function relates the adiabatic deformation of the electronic band structure to the vibration of the ion cores. Expressions for the dynamical matrices are derived. The model is ready for a direct computer evaluation of the phonon frequencies to test its validity.