Isothermal compressibility of the liquid alkali metals

Abstract

A corresponding-states correlation, based on the radial distribution function, is established which describes the temperature dependence of the isothermal compressibilities of liquid sodium, potassium, rubidium and cesium. It is shown that if the liquid alkali metals follow the same form of a two-parameter intermolecular potential energy function, then a simple relationship should exist between reduced compressibility and reduced temperature. Independently determined parameters are used to define the reduced quantities and to establish the relationship. The correlation can be used to predict the compressibility of lithium (for which no data are presently available) and to extend the data for rubidium and cesium to temperatures above the experimental range.