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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: POSTERS Dynamics and Diffusion
CPP 8.16: Poster
Monday, February 25, 2008, 16:45–19:00, Poster A
Soft spots of hard spheres — •Erik Lange — University of Konstanz
The influence of the potential shape on the structure and dynamics of a colloidal suspension has been of longstanding interest. We use simulations to tackle this question from a new angle.
Exploiting molecular dynamics simulations we find strong differences in the local structure for different potentials. Even a rescaling with respect to the distance from the freezing point does not reconcile this disagreement. However the structure factor
Sq= |
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| exp |
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shows a remarkable indifference towards subtleties in the potential.
The fact that a number of different systems display the same structural property suggests a closer look at the structural relaxation. As a result our work provides a clear tool to predict where differences should be negligible.
Indeed the longtime diffusion coefficients coincide as well as the stress-stress correlation at intermediate to long times.
So this is an approach that makes it clearer where softness matters and where hard spheres have soft spots.