Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 15: Colloids and Complex Fluids I (Joint Session CPP/BP/DY)
BP 15.5: Vortrag
Dienstag, 21. März 2017, 12:30–12:45, ZEU 255
Determination of crystal nucleation barriers for colloidal crystals from computer simulations — •Peter Koss1,2, Antonia Statt3, Peter Virnau1, and Kurt Binder1 — 1Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 9, 55128 Mainz, Germany — 2Graduate School of Excellence Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany — 3Princeton University, Princeton, NJ 08544, USA
A fluid in equilibrium, confined in a finite volume, with a density exceeding the onset of freezing, may exhibit phase coexistence with a crystal nucleus surrounded by liquid or a gas. Classical nucleation theory predicts that the barrier of homogeneous nucleation is given by two contributions, the free energy gained by the creation of a crystal droplet and the free energy loss due to surface tension of the newly created interface. We obtain the excess free energy due to the surface of the crystalline nucleus by using a computational method suitable for the estimation of the chemical potential of dense fluids. Our analysis method is appropriate for crystal nuclei of all shapes, without suffering from ambiguities occurring when one needs a microscopic identification of the crystalline droplet. We present a novel analysis method to determine the coexistence pressure between fluid and crystal, and report that the nucleation barrier for a soft version of the effective Asakura-Oosawa model is compatible with a spherical shape, and consistent with classical nucleation theory [1].
[1] A. Statt, P. Virnau, and K. Binder, Phys. Rev. Lett. 114, 026101 (2015).