Effect of hydrostatic pressure on the electronic dielectric constant of ionic crystals

Abstract

The strain derivatives of the electronic dielectric constant in LiF, NaCl, KCl, KBr, KI, RbCl and MgO crystals have been calculated with the help of the Clausius-Mossotti model. The variation of electronic polarizabilities with compressive stress has been derived by taking into account the distortion of ions, within the framework of the deformation dipole model. It has been observed that consideration of the variation of polarizabilities with compressive stress improves the agreement between theory and experiment. The photoelastic behaviour of MgO is predicted to be of the opposite nature to that of alkali halides in conformity with the experimental observations.