Dresden 2006 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.120: Poster
Donnerstag, 30. März 2006, 16:00–18:00, P1
Molecular dynamics simulations of argon 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
The properties of noble gases like argon are well known experimentally and can be adequately described using a Lennard-Jones potential. This potential is in turn comparatively easy to use in more elaborate nucleation theories and simulations. Thus, noble gases are ideal to test different theoretical approaches. It was assumed that classical nucleation theory (CNT) describes an almost ideal substance like argon much better than e.g. water [1]. Yet, recent experiments on argon nucleation show enormous deviations from CNT of up to 26 orders of magnitude [3]. We carried out MD simulations of vapor-liquid argon nucleation to investigate if these results are confirmed. Five different supersaturations were simulated at five temperatures similar to the experiment. Each set consists of up to 1000 simulation runs for better statistics. The nucleation rate isotherms yield the critical cluster size n* based on thermodynamic arguments. Also, we introduce a new approach based on rate theory to analyze the results. Thus, we can also determine n* directly from the kinetics without thermodynamical considerations. We compare these results with experiment and different theories.
[1] Wölk, Strey, J Phys Chem B 105, 11683 (2001)
[2] Iland, Dissertation, Universität zu Köln, 2004