Quasi-saddles as relevant points of the potential energy surface in the dynamics of supercooled liquids

TL;DR

This study investigates the potential energy surface of a supercooled Lennard-Jones liquid, revealing how relevant points called quasi-saddles relate to the dynamics and transition temperatures, with implications for understanding glassy behavior.

Contribution

It introduces the concept of quasi-saddles as relevant points on the potential energy surface and links their properties to the dynamics of supercooled liquids, extending previous landscape models.

Findings

Number of negative curvatures extrapolates to zero at T_c

Temperature dependence of negative curvatures relates to diffusivity

Potential energy landscape shows high regularity in distances and energies

Abstract

The supercooled dynamics of a Lennard-Jones model liquid is numerically investigated studying relevant points of the potential energy surface, i.e. the minima of the square gradient of total potential energy $V$. The main findings are: ({\it i}) the number of negative curvatures $n$ of these sampled points appears to extrapolate to zero at the mode coupling critical temperature $T_c$; ({\it ii}) the temperature behavior of $n(T)$ has a close relationship with the temperature behavior of the diffusivity; ({\it iii}) the potential energy landscape shows an high regularity in the distances among the relevant points and in their energy location. Finally we discuss a model of the landscape, previously introduced by Madan and Keyes [J. Chem. Phys. {\bf 98}, 3342 (1993)], able to reproduce the previous findings.