Structure and phase equilibria of the Widom-Rowlinson model

TL;DR

This paper combines computer simulation, density functional theory, and integral equation theory to accurately predict the microscopic structure and phase equilibria of the Widom-Rowlinson model, a key system in phase transition studies.

Contribution

It introduces a new closure for Ornstein-Zernike equations that accurately describes pair structure and locates the critical point within 2 percent.

Findings

Accurate prediction of pair correlation functions

Critical point located within 2% accuracy

Good agreement between theory and simulation

Abstract

The Widom-Rowlinson model plays an important role in the statistical mechanics of second order phase transitions and yet there currently exists no theoretical approach capable of accurately predicting both the microscopic structure and phase equilibria. We address this issue using computer simulation, density functional theory and integral equation theory. A detailed study of the pair correlation functions obtained from computer simulation motivates a closure of the Ornstein-Zernike equations which gives a good description of the pair structure and locates the critical point to an accuracy of 2 percent.