Is there a third order phase transition for supercritical fluids?

TL;DR

This study uses Molecular Dynamics simulations to investigate the existence of a third order phase transition in supercritical fluids, challenging recent theoretical and experimental claims of its universality.

Contribution

It provides evidence against the existence of a third order phase transition in supercritical fluids, based on MD simulations of Lennard-Jones liquids, questioning prior theoretical and experimental findings.

Findings

No third order phase transition observed in MD simulations

Results suggest smooth thermodynamic behavior in supercritical regime

Contradicts previous studies claiming universality of the transition

Abstract

We prove that according to Molecular Dynamics (MD) simulations of liquid mixtures of Lennard-Jones (L-J) particles, there is no third order phase transition in the supercritical regime beyond Andrew's critical point. This result is in open contrast with recent theoretical studies and experiments which instead suggest not only its existence but also its universality regarding the chemical nature of the fluid. We argue that our results are solid enough to go beyond the limitations of MD and the generic character of L-J models, thus suggesting a rather smooth liquid-vapor thermodynamic behavior of fluids in supercritical regime.