Influence of attractive parts of interaction potentials on critical point parameters

TL;DR

This paper analyzes how microscopic features of interparticle potentials, specifically Morse and Curie-Weiss types, influence the macroscopic critical point parameters in many-particle systems, using analytical and numerical methods.

Contribution

It introduces an analytical approach to connect microscopic potential features with critical point parameters for Morse and Curie-Weiss potentials, including numerical results for alkali metals.

Findings

Critical point parameters vary with microscopic potential features.

Numerical results for Na and K match experimental data.

Varying attraction strength affects critical point coordinates.

Abstract

We investigate how microscopic features of interparticle potentials influence macroscopic critical point parameters. Our analytical calculations are based on the cell model for continuous many-particle systems. We explore two types of pair interactions described by the Morse potential and a Curie-Weiss-type potential. For Morse fluids, we present numerical results obtained with microscopic parameters corresponding to the alkali metals sodium (Na) and potassium (K). The calculated dimensionless critical point parameters for liquid Na and K, expressed in dimensional units, allow for direct comparison with available experimental and simulation data. For the Curie-Weiss cell model with competing interactions, which exhibits a sequence of first-order phase transitions, we examine the critical parameters for the first three critical points. We analyze our results by varying the attractive part of the Morse potential and the Curie-Weiss attraction strength, providing insights into how these microscopic characteristics change critical point coordinates.