Dresden 2006 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.57: Poster
Donnerstag, 30. März 2006, 16:00–18:00, P1
Effects of carrier gas and different thermostats in molecular dynamics simulations of vapor-liquid nucleation — •Jan Wedekind1, David Reguera2, and Reinhard Strey1 — 1Institut für Physikalische Chemie, Universität zu Köln, Luxemburger Str. 116, D-50939 Köln, Germany — 2Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès, 1, 08028-Barcelona, Spain
Nucleation is the first step in most first-order phase transitions such as condensation. As an activated process, it is highly sensitive to small changes in temperature leading to differences in nucleation rates of up to several orders of magnitude. In molecular dynamics (MD) simulations it is not a trivial task to keep the temperature constant. One way is to directly thermostat the vapor itself. However, this may lead to an undesirable change of the temperature of a condensing cluster. Another approach mimicing the experiment is to thermostat the condensable species through their collisions with a carrier gas. We investigated the influence of a carrier gas in a MD simulation of nucleation of Lennard-Jones argon. We simulated a system at two different supersaturations without and with three different concentrations of carrier gas. Each simulation was repeated up to 1000 times yielding a previously unmatched accuracy of the statistics. It turns out that the choice of thermostat does not have a significant influence on the results of argon nucleation, even though this result may not be generalized to any kind of nucleation system or nucleating species.