General features of the energy landscape in Lennard-Jones like model liquids

TL;DR

This study investigates the energy landscape of Lennard-Jones-like liquids, revealing universal features and a direct link between landscape properties and the dynamical slowdown near the mode-coupling temperature T_MCT.

Contribution

It demonstrates the universality of the energy landscape shape across different systems and establishes a quantitative relationship between T_MCT and potential energy barriers.

Findings

Quasisaddle order approaches zero at T_MCT.

Universal landscape features across different systems.

Quantitative link between T_MCT and energy barriers.

Abstract

Features of the energy landscape sampled by supercooled liquids are numerically analyzed for several Lennard-Jones like model systems. The properties of quasisaddles (minima of the square gradient of potential energy W=|grad V|^2), are shown to have a direct relationship with the dynamical behavior, confirming that the quasisaddle order extrapolates to zero at the mode-coupling temperature T_MCT. The same result is obtained either analyzing all the minima of W or the saddles (absolute minima of W), supporting the conjectured similarity between quasisaddles and saddles, as far as the temperature dependence of the properties influencing the slow dynamics is concerned. We find evidence of universality in the shape of the landscape: plots for different systems superimpose into master curves, once energies and temperatures are scaled by T_MCT. This allows to establish a quantitative relationship between T_MCT and potential energy barriers for LJ-like systems, and suggests a possible generalization to different model liquids.