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DY: Fachverband Dynamik und Statistische Physik

DY 2: Statistical Physics (general)

DY 2.4: Vortrag

Montag, 14. März 2011, 11:00–11:15, ZEU 255

Binary nucleation: molecular dynamics simulation of the n-nonane/methane system — •Stephan Braun and Thomas Kraska — Institute of Physical Chemistry, University of Cologne, Luxemburger Str. 116, D-50939 Köln

Molecular dynamics simulation is employed to investigate the vapour-liquid nucleation of the binary system n-nonane/methane. The supersaturation of the system is achieved by cooling down the system during expansion in order to closely mimic the real process which is in practice applied, for example, to separate heavy compounds from natural gas.

By means of molecular dynamics simulations it is possible to obtain several details of the nucleation process, which are difficult or impossible to obtain from experiments. This regards the early stages of nucleation and growth taking place on the nanosecond time scale. Properties such as the nucleation rates or the critical cluster size can be determined even at high pressures. Furthermore, the determination of the composition of the clusters and the cluster structure can help to understand the nucleation process. Simulations where performed at different temperatures and densities for systems with various mole-fractions. The resulting nucleation rates have been compared to nucleation theory and the obtained clusters where analyzed with regard to structure and composition to understand possible effects on the nucleation process.