Improved first order mean spherical approximation for simple fluids

TL;DR

This paper introduces an improved perturbation method based on the first-order mean spherical approximation, using a Yukawa fluid as a reference, which enhances accuracy in predicting thermodynamic properties of simple fluids.

Contribution

It proposes a novel perturbation approach with a Yukawa reference system, improving the accuracy of FMSA predictions while maintaining simplicity.

Findings

Enhanced accuracy over conventional FMSA/HS in predicting compressibility factors.

Better agreement with Monte Carlo simulation data for vapor-liquid phase diagrams.

Maintains simplicity and transparency of the original FMSA approach.

Abstract

A perturbation approach based on the first-order mean spherical approximation (FMSA) is proposed. It consists in adopting a hard-sphere plus short-range attractive Yukawa fluid as the novel reference system, over which the perturbative solution of the Ornstein-Zernike equation is performed. A choice of the optimal range of the reference attraction is discussed. The results are compared against conventional FMSA/HS theory and Monte-Carlo simulation data for compressibility factor and vapor-liquid phase diagrams of the medium-ranged Yukawa fluid. Proposed theory keeps the same level of simplicity and transparency, as the conventional FMSA/HS approach does, but shows to be more accurate.