Screened Coulomb Potential in KCl Crystal

Abstract

The wave-number-dependent dielectric function is calculated for crystalline KCl, on the basis of the expressions derived in a previous paper. The value, 2.383, is obtained for the static dielectric constant in long wave length limit, which is to be compared with the observed optical dielectric constant ε_∞=2.13. The contribution from the Umklapp terms has turned out to be rather small. An approximate analytical expression is presented for the screened Coulomb potential in KCl crystal.