Phase diagram and structural properties of a simple model for one-patch particles

TL;DR

This paper investigates the phase diagram and structural characteristics of a one-patch particle model using RHNC integral equations and Monte Carlo simulations, revealing reliable predictions of fluid-fluid separation and detailed structural insights.

Contribution

It introduces a combined theoretical and simulation approach to accurately predict phase behavior and structural properties of one-patch particles, highlighting RHNC's effectiveness.

Findings

RHNC accurately estimates the fluid-fluid critical line.

Structural properties depend strongly on patch size.

Good agreement between RHNC and Monte Carlo results.

Abstract

We study the thermodynamic and structural properties of a simple, one-patch fluid model using the reference hypernetted-chain (RHNC) integral equation and specialized Monte Carlo simulations. In this model, the interacting particles are hard spheres, each of which carries a single identical, arbitrarily-oriented, attractive circular patch on its surface; two spheres attract via a simple square-well potential only if the two patches on the spheres face each other within a specific angular range dictated by the size of the patch. For a ratio of attractive to repulsive surface of 0.8, we construct the RHNC fluid-fluid separation curve and compare with that obtained by Gibbs ensemble and grand canonical Monte Carlo simulations. We find that RHNC provides a quick and highly reliable estimate for the position of the fluid-fluid critical line. In addition, it gives a detailed (though approximate) description of all structural properties and their dependence on patch size.