Distribution of ions in electrolyte solutions and plasmas. Part 4.—Concentrated electrolyte solutions

Abstract

In Parts 1–3 of this series the distribution of ions in dilute electrolyte solutions was investigated. In Part 4 we extend the statistical mechanical treatment already developed to examine more concentrated solutions. Expressions are obtained for the binary distribution function F_ji and the mean electrostatic potential ψ_j which are suitable for systems where the dielectric constant of the solvent and the charge type and concentration of the electrolyte are such that the parameter t(=κR) lies in the range 0–2 (t= 2 corresponds to a 2 mol dm^–3 solution of a 1:1 salt in water at 25 °C). The distribution function obtained is shown to satisfy the “Second Moment” condition of Stillinger and Lovett to terms of the order t² and to show little deviation from this condition even at concentrations corresponding to t= 2. The present treatment is compared with that of Kirkwood and of Outhwaite et al.