A repulsive reference potential reproducing the dynamics of a liquid with attractions

TL;DR

This paper demonstrates that a repulsive inverse-power law potential can serve as an effective reference for modeling the structure and dynamics of a Lennard-Jones liquid, outperforming the traditional WCA potential.

Contribution

The authors introduce a repulsive inverse-power law potential as a new reference that accurately reproduces the structure, dynamics, and thermodynamics of a Lennard-Jones liquid.

Findings

Inverse-power law potential matches the liquid's structure.

It accurately reproduces the liquid's dynamics.

It captures the isochoric heat capacity of the liquid.

Abstract

A well-known result of liquid state theory is that the structure of dense fluids is mainly determined by repulsive forces. The WCA potential, which cuts intermolecular potentials at their minima, is therefore often used as a reference. However, this reference gives quite wrong results for the viscous dynamics of the Kob-Andersen binary Lennard-Jones liquid [Berthier and Tarjus, Phys. Rev. Lett. 103, 170601 (2009)]. We show that repulsive inverse-power law potentials provide a useful reference for this liquid by reproducing its structure, dynamics, and isochoric heat capacity.