Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 31: Phase Transitions and Critical Phenomena

DY 31.8: Vortrag

Freitag, 30. März 2012, 11:45–12:00, MA 004

Properties of stable and metastable crystals and interfaces in the hard sphere system — •Mohammad Hossein Yamani and Martin Oettel — Institute of Physics, Johannes Gutenberg University, Mainz, Germany

Colloidal hard spheres are an intensely studied model system for addressing the nucleation problem. Understanding homogeneous and heterogeneous nucleation requires a precise knowledge about equilibrium crystal structures, crystal-liquid surface tensions and interface tensions with substrates. Density Functional Theory (DFT) as one of the core theoretical approaches of statistical physics of fluids and crystals, is able to treat such an important system successfully and accurately. We use density functional theory of fundamental measure type (FMT) to obtain the fully minimized periodic FCC crystal profiles and wall-liquid interface tensions and compare to new, accurate simulation data. Furthermore we present first DFT results obtained by unconstrained minimization for free energies of metastable BCC and HCP crystals. DFT results in the case of FCC compare very well to simulation results. HCP and FCC differ only in the stacking sequence of hexagonally packed planes of particles, and thus one expects only a small free-energy difference between these two structures. We present preliminary results obtained by FMT for the differences between FCC and HCP in free-energy and in the unit cell density distribution.