Use of the attractive hard-core Yukawa interaction for the derivation of the phase diagram of liquid water

TL;DR

This paper uses an attractive hard-core Yukawa model with a temperature rescaling technique to accurately approximate the phase diagram of liquid water, including coexistence curves and critical points, with some limitations near the triple point.

Contribution

It introduces a novel temperature rescaling method applied to the Yukawa fluid model to replicate water's phase diagram with improved accuracy.

Findings

Successfully reproduces water's phase diagram features

Provides a physically interpretable temperature-dependent potential

Achieves good agreement with experimental data away from triple point

Abstract

The phase diagram of the attractive hard-core Yukawa fluid derived previously [M. Robles and M. L\'opez de Haro, J. Phys. Chem. C 111, 15957 (2007)] is used to obtain the liquid-vapor coexistence curve of real water. To this end, the value of the inverse range parameter of the intermolecular potential in the Yukawa fluid is fixed so that the ratio of the density at the critical point to the liquid density at the triple point in this model coincides with the same ratio in water. Subsequently, a (relatively simple) nonlinear rescaling of the temperature is performed which allows one to obtain the full liquid vapor coexistence curve of real water in the temperature-density plane with good accuracy, except close to the triple point. Such rescaling may be physically interpreted in terms of an effective temperature-dependent attractive hard-core Yukawa interaction potential which in turn introduces an extra temperature dependence in the equation of state. With the addi- tion of a multiplicative factor to obtain from the model the critical pressure of real water, the corrected equation of state yields reasonably accurate isotherms in the liquid phase region except in the vicinity of the critical isotherm and in the vicinity of the triple point isotherm. The liquid-vapor coexistence curves in the pressure-temperature and pressure-density planes are also computed and a possible way to improve the quantitative agreement with the real data is pointed out.