Hypernetted-Chain Approximation Applied to a Modified Lennard-Jones Fluid

Abstract

The hypernetted‐chain approximation is used in conjunction with Baxter's form of the Ornstein–Zernicke equation to predict the thermodynamic properties of a Lennard‐Jones fluid. It is shown that the approximation predicts a phase change for the fluid. Outside the critical region the HNC equation is at least two valued for all densities in the range (0–0.6). The critical temperature obtained from the approximation is dependent upon the range of the intermolecular potential function, but the critical density is relatively insensitive. Unlike the behavior reported for the Percus–Yevick approximation, the compressibility of the fluid does not become infinite at the phase change.