New criteria for the equation of state development: Simple model fluids

TL;DR

This paper introduces a generalized density rescaling method for simple fluids with various pair potentials, revealing linear relationships among critical parameters and suggesting a near-universal critical compressibility factor.

Contribution

It extends a previous rescaling approach to a broader class of model fluids, establishing new linear correlations among critical properties.

Findings

Critical pressure and temperature are linearly related.

Critical density and inverse critical temperature are linearly related.

Critical compressibility factor approximates the universal experimental value.

Abstract

Recently we have proposed (J. Chem. Phys. 128 (2008) 134508) a new rescaling of fluid density $\rho $ by its critical value $\rho_c^{2/3}$ to apply the corresponding states law for the attractive Yukawa fluids study. Analysis of precise simulation results allows us to generalize this concept to the case of simple fluids with different interparticle interactions, like Mie (n,m) and Sutherland pair potentials. It is shown, that there is a linear relationship between the critical pressure and critical temperature, as well as the critical density and inverse critical temperature for these frequently used pair potentials. As a consequence, the critical compressibility factor of these model fluids is close to its universal value measured experimentally for different real substances.