Glass Transition Line in C₆₀:  A Mode-Coupling/Molecular-Dynamics Study

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 side of 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.

C60: The First One-Component Gel?

“…The Girifalco potential is plotted in 1. This Girifalco model is known to undergo dynamical arrest at high temperature and density [25][26][27]. The glass line intersects the gas-liquid spinodal at around T G ≈ 1100 K, while crystallisation is expected at higher temperature [25].…”

“…This Girifalco model is known to undergo dynamical arrest at high temperature and density. [25][26][27] The glass line intersects the gas-liquid spinodal at around T G ≈ 1100 K, whereas crystallization is expected at higher temperature. 25 While locally crystalline structures still meet our criterion for gelation (i.e., a longlived network), the absence of vitrification of the dense phase suggests that demixing may proceed.…”

Mesoscopic Interaction Potential for Carbon Nanotubes of Arbitrary Length and Orientation

“…The effective potentials describe the nonbonding interactions between the graphitic structures at a mesoscopic rather than atomistic level, expressing the interaction energies in the form of simple functions that depend only on the distance between interacting objects. Moreover, when expressed in terms of reduced parameters, the interactions derived for different graphitic structures are found to be well represented by a universal graphitic potential. − While the effective mesoscopic potential for fullerene molecules and graphene have already found applications in large-scale mesoscopic simulations of fullerene films, clusters, and bulk structures, e.g., refs and − , the application of the potential for CNTs is limited by the geometrical limitations of the modelsall derivations have been performed for straight, infinitely long, parallel CNTs. − The only CNT systems that can be investigated with the current models are bundles of straight infinitely long nanotubes. ,,, …”