Thermodynamically self-consistent theories of simple liquids

Abstract

A new functional derivative approach is used to derive an approximate integral equation relating the radial distribution function to the interaction potential of a simple liquid. Parameters contained in the theory are chosen so that consistency is achieved between the pressure and compressibility equations of state, and so that a new condition, also derived in the paper, is satisfied. Results of calculations for the hard sphere fluid virial coefficients and equation of state are presented and found to be in excellent agreement with molecular dynamics simulations. The use of these results as a basis for a perturbation theory of simple liquids with more realistic interaction potentials is also discussed.