Glass transition line in C60: a mode-coupling/molecular-dynamics study

TL;DR

This study uses mode-coupling theory and molecular dynamics simulations to map the glass transition line in a C60 fullerene model, confirming the existence of a glassy phase and accurately predicting its location.

Contribution

It provides the first detailed MCT-based analysis of the glass transition line for the Girifalco C60 model using simulation-derived structure factors.

Findings

The glass transition line lies within the metastable liquid-solid coexistence region.

The vitrification locus does not exhibit re-entrant behavior.

The MCT predictions closely match previous simulation estimates.

Abstract

We report a study of the mode-coupling theory (MCT) glass transition line for the Girifalco model of C60 fullerene. The equilibrium static structure factor of the model, the only required input for the MCT calculations, is provided by molecular dynamics simulations. The glass transition line develops inside the metastable liquid-solid coexistence region and extends down in temperature, terminating on the liquid sideof the metastable portion of the liquid-vapor binodal. The vitrification locus does not show re-entrant behavior. A comparison with previous computer simulation estimates of the location of the glass line suggests that the theory accurately reproduces the shape of the arrest line in the density-temperature plane. The theoretical HNC and MHNC structure factors (and consequently the corresponding MCT glass line) compare well with the numerical counterpart. These evidences confirm the conclusion drawn in previous works about the existence of a glassy phase for the fullerene model at issue.