Characterizing Translational and Rotational Dynamical Heterogeneity in a Supercooled Glass-Forming Diatomic Liquid*

A glass forms when a supercooled liquid solidifies via a rapid increase in viscosity rather than by crystallization. We use molecular dynamics simulations to investigate a 3D supercooled liquid of diatomic rigid molecules interacting via the Lennard-Jones potential. We measure correlation functions and local order parameters for translational and orientational degrees of freedom to characterize the system's static and dynamic behaviors. We introduce new observables to probe the rotational behavior and we investigate the heterogeneous dynamics of both the translation and rotational degrees of freedom. We also characterize the geometry of the heterogeneous regions.