Dresden 2009 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 26: Poster II
DY 26.6: Poster
Donnerstag, 26. März 2009, 16:00–18:00, P1A
Collective dynamics of simple liquids: A mode-coupling description — •Bernhard Schmid1, Walter Schirmacher1, Harald Sinn2, and Rolf Schilling1 — 1Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, D-55099 Mainz, Germany — 2Hasylab/DESY, Notkestraße 85, D-22607 Hamburg, Germany
We use the mode-coupling theory (MCT), which has been highly successful in accounting for the anomalous relaxation behaviour near the liquid-to-glass transition, for describing the dynamics of monoatomic (i.e. simple) liquids away from the glass formation regime. We find that the dynamical structure factor predicted by MCT compares well to experimental findings and results of computer simulations [1]. We have studied in particular the dynamics of Lennard-Jones Argon and compared the predicted dynamical structure factor S( k,ω ) with simulation data. The memory function M( k,t) exhibits a two-step decay. The existence of such a two-step decay of M( k,t) has already been predicted by Levesque et al. [2] but never been explained. We can show that the long-time relaxation process which strongly depends on density can be identified as the α -relaxation associated with the cage effect. The short-time, almost density independent relaxation is of microscopic origin.
[1] W. Schirmacher, H. Sinn, J. Condens. matter 11, 127 (2008)
[2] D. Levesque, L. Verlet, and J. Kurkijärvi, Phys. Rev. A 7, 1690 (1973)