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arXiv · 0710.3111

Long-time self-diffusion of Brownian Gaussian-core particles

H. H. Wensink·H. Löwen·M. Rex·C. N. Likos·S. van Teeffelen
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Abstract

Using extensive Brownian dynamics computer simulations, the long-time self-diffusion coefficient is calculated for Gaussian-core particles as a function of the number density. Both spherical and rod-like particles interacting via Gaussian segments ar$ For increasing concentration we find that the translational self-diffusion behaves non-monotonically reflecting the structural reentrance effect in the equilibrium phase diagram. Both in the limits of zero and infinite concentration, it approaches its short-time value. The microscopic Medina-Noyola theory qualitatively accounts for the translational long-time diffusion. The long-time orientational diffusion coefficient for Gaussian rods, on the other hand, remains very close to its short-time counterpart for any density. Some implications of the weak translation-rotation coupling for ultrasoft rods are discussed.

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H. H. Wensink, H. Löwen, M. Rex, C. N. Likos, S. van Teeffelen. 2007-10-16. Long-time self-diffusion of Brownian Gaussian-core particles. https://doi.org/10.1016/j.cpc.2008.01.009

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