Electronic polarizabilities of Tl+, Ag+, and Zn2+ ions estimated from refractive index measurements of TlNO3, AgNO3, and ZnCl2 melts

Abstract

Refractive indices of TlNO3, AgNO3, and ZnCl2 ionic melts were measured by a goniometer method using visible light at nine wavelengths. The refractive indices of these pure melts were represented conveniently as functions of both temperature and wavelength by means of a two-dimensional least squares method. According to the obtained formulas, the refractive indices were extrapolated to infinite wavelength so that the electronic polarizabilities of Tl+, Ag+, and Zn2+ ions in each pure melt were evaluated in terms of the Clausius–Mossotti equation to be 4.16, 2.07, and 0.78 A3 at 420 °C, respectively. It was made clear even in the molten state, by correlating the electronic polarizabilities of ions with the ionic radii, that the electronic polarizabilities were unequivocally governed by the electron configuration as well as being affected by the ionic radii.