# Virial coefficients, equation of state, and demixing of binary asymmetric nonadditive hard-disk mixtures

## TL;DR

This paper reports on the calculation of virial coefficients, equation of state, and phase coexistence in binary asymmetric nonadditive hard-disk mixtures using Monte Carlo simulations, providing new data and comparisons with theoretical models.

## Contribution

It introduces comprehensive Monte Carlo simulation data for virial coefficients and phase behavior in asymmetric nonadditive hard-disk mixtures, expanding understanding of their thermodynamics.

## Key findings

- Virial coefficients for various size ratios and nonadditivities calculated.
- Equation of state derived from simulations for different compositions.
- Fluid-fluid coexistence curves obtained and compared with theoretical models.

## Abstract

Values of the fifth virial coefficient, compressibility factors, and fluid-fluid coexistence curves of binary asymmetric nonadditive mixtures of hard disks are reported. The former correspond to a wide range of size ratios and positive nonadditivities and have been obtained through a standard Monte Carlo method for the computation of the corresponding cluster integrals. The compressibility factors as functions of density, derived from canonical Monte Carlo simulations, have been obtained for two values of the size ratio ($q=0.4$ and $q=0.5$), a value of the nonadditivity parameter $\Delta=0.3$), and five values of the mole fraction of the species with the biggest diameter ($x_1=0.1$, $0.3$, $0.5$, $0.7$, and $0.9$). Some points of the coexistence line relative to the fluid-fluid phase transition for the same values of the size ratios and nonadditivity parameter have been obtained from Gibbs Ensemble Monte Carlo simulations. A comparison is made between the numerical results and those that follow from some theoretical equations of state.