Properties of ideal Gaussian glass-forming systems

TL;DR

This paper introduces the ideal Gaussian glass-forming system model, linking potential energy landscape properties to supercooled liquids' thermodynamics and dynamics, enabling analytical predictions of key observables.

Contribution

It presents a novel model that analytically relates the potential energy landscape to glass-forming behavior, compatible with simulations and experiments.

Findings

Analytical expressions for diffusion constants and relaxation times.

Identification of a key PEL parameter influencing fragility.

Reproduction of several experimental observations.

Abstract

We introduce the ideal Gaussian glass-forming system as a model to describe the thermodynamics and dynamics of supercooled liquids on a local scale in terms of the properties of the potential energy landscape (PEL). The first ingredient is the Gaussian distribution of inherent structures, the second a specific relation between energy and mobility. This model is compatible with general considerations as well as with several computer simulations on atomic computer glass-formers. Important observables such as diffusion constants, structural relaxation times and kinetic as well as thermodynamic fragilities can be calculated analytically. In this way it becomes possible to identify a relevant PEL parameter determining the kinetic fragility. Several experimental observations can be reproduced. The remaining discrepancies to the experiment can be qualitatively traced back to the difference between small and large systems.