Geometrical characterization of hard-sphere systems

By using molecular dynamics simulations on a large number of hard spheres and the Voronoi tessellation we characterize hard-sphere systems geometrically at any packing fraction eta along the different branches of the phase diagram. Crystallization of disordered packings occurs only for a small range of packing fraction. For the other packing fractions the system behaves as either a fluid (stable or metastable) or a glass. We have studied the evolution of the statistics of the Voronoi tessellation during crystallization and characterized the apparition of order by an order parameter (Q(6)) built from spherical harmonics. [S1063-651X(99)19510-2].