Continuum percolation of simple fluids: Energetic connectivity criteria

TL;DR

This paper investigates the energetic connectivity criterion for percolation in simple fluids, showing that velocity-averaged versions overestimate percolation densities and proposing a method to improve predictions using molecular dynamics and integral equation theory.

Contribution

The study demonstrates the limitations of velocity-averaged criteria in predicting percolation and introduces an improved approach based on molecular dynamics and advanced integral equation theory.

Findings

Velocity-averaged criteria overestimate percolation densities.

Molecular dynamics simulations reveal discrepancies in Lennard-Jones fluids.

A new integral equation approach improves percolation predictions.

Abstract

During the last few years, a number of works in computer simulation have focused on the clustering and percolation properties of simple fluids based in an energetic connectivity criterion proposed long ago by T.L. Hill [J. Chem. Phys. 23, 617 (1955)]. This connectivity criterion appears to be the most appropriate in the study of gas-liquid phase transition. So far, integral equation theories have relayed on a velocity-averaged version of this criterion. We show, by using molecular dynamics simulations, that this average strongly overestimates percolation densities in the Lennard-Jones fluid making unreliable any prediction based on it. Additionally, we use a recently developed integral equation theory [Phys. Rev. E 61, R6067 (2000)] to show how this velocity-average can be overcome.