Empirical relationship between effective ionic charges and optical dielectric constantsin binary and ternary cubic compounds

The effective ionic charge Ze of each ion is determined within a narrow variable range for cubic and near-cubic ternary compounds. The Szigeti effective charge e(/sub s/[ = 3√epsilon-bar/sub proportional/Z(e/(epsilon/sub proportional/+2)] is also evaluated for the anion from the value Z*e by using the observed optical dielectric constant epsilon/sub infinity/. The correlation between e(/sub s/ and the dielectric constant epsilon/sub infinity/ is empirically found for many kinds of binary and ternary compounds as epsilon/sub infinity/-1 = 2.0/ [(e(/sub s//Z/sub eff/e)+(e(/sub s//Z/sub eff/e)2]. The value Z/sub eff/ indicates the effective chemical valency. In the correlation, the relatively large scatter for some compounds is explained by the d- or f-electron effect on the dielectric constant epsilon/sub infinity/, and by the screening and the anisotropic effects on the effective charge. From these results, the applicable ranges of the equation used and of the localized effective charge are discussed