Volume dependence of dielectric properties of some fluorite-structure crystals

The experimental data on first and second order pressure derivatives of dielectric constants are used to make an analysis of the volume dependence of polarizabilities, effective charge parameter, and transverse-optic-mode frequencies in CaF2, SrF2, BaF2, PbF2, Sr(NO3)2, Ba(NO3)2, and Pb(NO3)2. The short range force constant responsible for the ion-displacement polarizability is calculated with the help of Lundqvist's three-body interaction model. Reasonable values for the volume derivatives of various dielectric parameters are obtained. Values of optic-mode-Grueneisen parameters and their volume derivatives are also calculated and compared with available experimental data. (author)