Regensburg 2013 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 25: Critical Phenomena and Phase Transitions

DY 25.5: Talk

Thursday, March 14, 2013, 10:30–10:45, H46

MC test of cluster definitions in nucleation simulations of the lattice gas model — •Fabian Schmitz, Peter Virnau, and Kurt Binder — Johannes Gutenberg-Universität Mainz - Staudingerweg 7, D-55099 Mainz, Germany

The conventional theory of homogeneous and heterogeneous nucleation in a supersaturated vapor is tested by Monte Carlo simulations of the lattice gas (Ising) model with nearest-neighbor attractive interactions on the simple cubic lattice. The theory considers the nucleation process as a slow (quasi-static) cluster (droplet) growth over a free energy barrier Δ F^*, constructed in terms of a balance of surface and bulk term of a “critical droplet” of radius R^*, implying that the rates of droplet growth and shrinking essentially balance each other for droplet radius R=R^*.

Comparing different cluster definitions, namely geometrical clusters, Swendsen-Wang clusters and clusters applying the relations from classical nucleation theory, we find that, for all temperatures below the critical temperature, only the definition of “physical” clusters based on the Fortuin-Kasteleyn mapping is consistent with the estimates from the lever rule. The discrepancy between classical nucleation theory and the lever rule is determined for various temperatures.