Does the interaction potential determine both the fragility of a liquid and the vibrational properties of its glassy state?

TL;DR

This study uses molecular dynamics simulations to demonstrate that the interaction potential's anharmonicity influences both the fragility of liquids and their vibrational properties in the glassy state, revealing a fundamental link between these features.

Contribution

It shows that the anharmonicity and intermolecular coupling capacity of the potential determine liquid fragility and vibrational behavior in glasses, providing a unified explanation.

Findings

Increased anharmonicity correlates with higher fragility.

Intermolecular coupling capacity affects the temperature dependence of vibrational properties.

Results align with experimental observations by T. Scopigno et al.

Abstract

By performing molecular dynamics simulations of binary Lennard-Jones systems with three different potentials, we show that increase of anharmonicity and capacity for intermolecular coupling of the potential is the cause of (i) the increase of kinetic fragility and nonexponentiality in the liquid state, (ii) the Tg-scaled temperature dependence of the nonergodicity parameter determined by the vibrations at low temperatures in the glassy state. Naturally these parameters correlate with each other, as observed experimentally by T. Scopigno et al., Science 302, 849 (2003).