Crystallization of Spheres

摘要: Simplified computer models are used to gain insight into more complex real systems. In a reversion of this protocol, colloidal suspension submicron spherical particles, approximately hard and uniform, was recently crystallized in space analyzed for crystal type. The objective establish how, what structure, spheres crystallize without gravity. Computational statistical thermodynamics predicts an equilibrium constant between fcc hcp order unity. microgravity experiments, however, resulted random hybrid close-packed structure (rhcp) such that long-range is two-dimensional. Here we report the mechanism from idealized “experiments” crystallization metastable fluid. Model systems up N=64,000 with infinite spatial periodicity have been runs 10 billion collisions. When fluid, initially supercooled state at 58% packing, allowed nucleate freeze, variety structures emerges. There three identifiable stages structural growth: (i) initial nucleation fcc, rhcp, also bcc-like (body-centered cubic) local structures; (ii) rapid growth all incipient nucleites stacked two-dimensional hexagonal grains, plus some fill volume; (iii) relatively slow dissolution unstable rhcp faces grain boundaries. Eventually, stable emerge comprising layers, arranged so as contain predominantly either arrangements or roughly 50% proportions.