Regensburg 2004 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.91: Poster

Donnerstag, 11. März 2004, 16:00–18:00, Poster D

Desorption behaviour of binary quench-condensed noble gas mixtures — •M. Layer, A. Netsch, A. Fleischmann, and S. Hunklinger — Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, D-69120 Heidelberg

Due to their simple van der Waals interaction noble gas crystals are commonly considered as model system for condensed matter. This holds in particular for binary mixtures. Freezing theories as well as molecular dynamical simulations predict the existence of structural ordered phases in good agreement with each other. We studied the desorption behaviour of quench-condensed noble gas films by means of high-frequency surface acoustic waves. In contrast to theoretical investigations quench-condensed films are in a state far away from thermal equilibrium. By annealing, these films are relaxing into thermodynamically more favorable phases. Over a wide range of preparation conditions (including substrate temperature, gas temperature, composition of the mixture) we found evidence for the formation of ordered film structures. Furthermore it turned out that in particular the ratio of diameters of the two components is relevant to the occurence of ordered film structures. Desorption processes of several condensed binary mixtures (Ne/Ar, Ne/Kr, Ar/Kr) are presented and the forming of possible van der Waals compounds is discussed.