Recasting a model atomistic glassformer as a system of icosahedra

TL;DR

This paper models a binary Lennard-Jones glassformer as an effective system of icosahedra, using a population dynamics approach to predict structural populations and relaxation behavior at various temperatures.

Contribution

It introduces a novel population dynamics model recasting the glassformer as an icosahedral system, enabling predictions beyond simulation temperature ranges.

Findings

Model predicts super-Arrhenius dynamics with finite relaxation times at non-zero temperatures.

Recovers temperature-dependent icosahedral populations from simulation data.

Extends understanding of glassy dynamics through an effective structural model.

Abstract

We consider a binary Lennard-Jones glassformer whose super-Arrhenius dynamics are correlated with the formation of icosahedral structures. Upon cooling these icosahedra organize into mesoclusters. We recast this glassformer as an effective system of icosahedra which we describe with a population dynamics model. This model we parameterize with data from the temperature regime accessible to molecular dynamics simulations. We then use the model to determine the population of icosahedra in mesoclusters at arbitrary temperature. Using simulation data to incorporate dynamics into the model we predict relaxation behavior at temperatures inaccessible to conventional approaches. Our model predicts super-Arrhenius dynamics whose relaxation time remains finite for non-zero temperature.