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CPP: Chemische Physik und Polymerphysik

CPP 1: Struktur und Dynamik in Polymersystemen I

CPP 1.1: Vortrag

Montag, 11. März 2002, 11:00–11:20, H38

Generating reweighting functions for simulations of phase equilibria — •Peter Virnau, Marcus Müller, Luis González MacDowell, and Kurt Binder — Institut für Physik, Staudinger Weg 7, 55099 Mainz

Grand-canonical Monte Carlo used in junction with histogram- reweighting techniques provide a powerful tool to study coexistence properties and interfaces. For temperatures below criticality states in the miscibility gap have a negligible weight. In general an a-priori unknown reweighting function has to be applied such that simulations sample all states with roughly equal probability.

We have developed two new approaches to generate reweighting functions in order to study LJ systems, liquid-vapor coexistence of polymers and compressible polymer-solvent mixtures. The first method is based on an umbrella-sampling scheme, the second on an algorithm previously devised by F.Wang and D.Landau [1]. These methods enable us to sample the phase diagram of binary mixtures as a function of pressure and composition in a single simulation run. We also applied these techniques to study finite-size effects in nucleation and to compare the results with classical nucleation theory.

[1] F.Wang and D.P.Landau, Phys.Rev.Lett. 86, 2050 (2001).