Yang-Yang Anomalies and Coexistence Diameters: Simulation of Asymmetric Fluids

TL;DR

This paper introduces a Monte Carlo simulation method to estimate the Yang-Yang ratio and coexistence-curve diameter in asymmetric fluids, accounting for pressure mixing in finite-size scaling.

Contribution

It presents a novel simulation approach that incorporates pressure mixing to analyze Yang-Yang anomalies in asymmetric fluid models.

Findings

Successful estimation of the Yang-Yang ratio ${\

Accurate evaluation of the coexistence-curve diameter.

Validation of the finite-size scaling theory with pressure mixing.

Abstract

A general method for estimating the Yang-Yang ratio, ${\cal R}_{\mu}$, and the coexistence-curve diameter of a model fluid via Monte Carlo simulations is presented on the basis of data for a hard-core square-well (HCSW) fluid and the restricted primitive model (RPM) electrolyte. The isothermal minima of $Q_{L}\equiv< m^{2}>^{2}_{L}/< m^{4}>_{L}$ are evaluated at $T_{c}$ in an $L\times L\times L$ box where $m = \rho - <\rho>_{L}$ is the density fluctuation. The ``complete'' finite-size scaling theory for the $Q_{\scriptsize min}^{\pm}(T_{c};L)$ incorporates pressure mixing in the scaling fields, thereby allowing for a Yang-Yang anomaly.