EQUATION OF STATE OF IONIC FLUIDS.

Abstract

An ionic fluid is modelled as a mixture of dipolar hard spheres (the solvent) and charged hard spheres (the ions). The free energy is expanded in a power series in the inverse temperature. Some of the terms in this expansion are infinite. However, these terms can be resummed to give a finite result. This expansion reduces to previously known results for pure dipolar hard spheres and pure charged hard spheres. As is the case for the pure dipolar and charged hard sphere systems, the convergence of the expansion can be enhanced by means of a Pade approximant. Simple expressions for the integrals appearing in the expansion are given.