In search of a thermodynamically self-consistent integral equation for linear molecular fluids

Abstract

We present a first exploratory attempt to build a closure relation for molecular fluids which, relying on the structure of the reference hypernetted chain approximation fulfils the conditions of thermodynamic consistency between the virial and fluctuation routes to evaluate the pressure. We report here results for two-centre Lennard-Jones fluids with and without embedded quadrupoles, which unequivocally show that a simple approximation that accounts roughly for the angular dependence of the bridge function plus the consistency criterion significantly improved upon the hypernetted chain equation results, particularly as far as thermodynamics is concerned.