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BP: Fachverband Biologische Physik

BP 45: Statistical Physics in Biological Systems III (Joint Session with DY)

BP 45.3: Talk

Wednesday, March 9, 2016, 16:00–16:15, H46

Geometry Dependence of the Diffusion Coefficient in Molecular Dynamics Simulations with Periodic Boundary Conditions — •Martin Vögele and Gerhard Hummer — Max-Planck-Institut für Biophysik, Frankfurt am Main

We investigate the dependence of the diffusion coefficient on the box geometry and its application to lipid membrane simulations.

For this purpose, we compare predictions from a simple analytic correction based on hydrodynamic arguments to molecular dynamics simulations of liquid argon. Increasing the box size in two dimensions, we find a logarithmic dependence on the system size. Increasing the box size in only one dimension, we find a linear dependence. In both cases, diffusion is anisotropic. Additionally, we observe an upper limit for the diffusion coefficient in the limit of infinite systems.

We also test the effect of box geometry on the diffusion in lipid membranes, which are usually simulated in very flat periodic boxes. There we find the predicted logarithmic increase with growing edge lengths.