Physics of the liquid-liquid critical point

TL;DR

This paper investigates the physics behind the liquid-liquid transition and density maxima in complex liquids like water by analyzing the potential energy landscape within the inherent structure formalism, establishing a link between anomalies and critical points.

Contribution

It introduces a novel analysis of the potential energy landscape's statistical properties related to liquid-liquid transitions and density anomalies, providing new insights into these phenomena.

Findings

Density anomalies imply the existence of a liquid-liquid transition.

Identification of statistical properties of the potential energy landscape responsible for anomalies.

Evidence of a connection between density maxima and the liquid-liquid critical point.

Abstract

Within the inherent structure (IS) thermodynamic formalism introduced by Stillinger and Weber [F. H. Stillinger and T. A. Weber, Phys. Rev. A {\bf 25}, 978 (1982)] we address the basic question of the physics of the liquid-liquid transition and of density maxima observed in some complex liquids such as water by identifying, for the first time, the statistical properties of the potential energy landscape (PEL) responsible for these anomalies. We also provide evidence of the connection between density anomalies and the liquid-liquid critical point. Within the simple (and physically transparent) model discussed, density anomalies do imply the existence of a liquid-liquid transition.