Event-driven simulation of the dynamics of hard ellipsoids

We introduce a novel algorithm to perform event-driven simulations of hard rigid bodies of arbitrary shape, that relies on the evaluation of the geometric distance. In the case of a monodisperse system of uniaxial hard ellipsoids, we perform molecular dynamics simulations varying the aspect-ratio X(0) and the packing fraction phi. We evaluate the translational D(trans) and the rotational D(rot) diffusion coefficient and the associated isodiffusivity lines in the phi -X(0) plane. We observe a decoupling of the translational and rotational dynamics which generates an almost perpendicular crossing of the D(trans) and D(rot) isodiffusivity lines. While the self intermediate scattering function exhibits stretched relaxation, i.e. glassy dynamics, only for large phi and X(0) approximate to 1, the second order orientational correlator C(2)(t) shows stretching only for large and small X(0) values. We discuss these findings in the context of a possible pre-nematic order driven glass transition.