Long-time self-diffusion for Brownian Gaussian-core particles
- 作者：H.H. Wensink ; H. Lö ; wen ; M. Rex ; C.N. Likos ; S. van Teeffelen
- 关键词：Self-diffusion ; Brownian dynamics ; Simulations ; Colloids
- 刊名：Computer Physics Communications
- 出版年：2008
- 期刊代码：30_00104655
- 类别：cp
- 出版时间：July 2008
- 卷：179
- 期：1-3
- 页码：77-81
- 文件大小：171 K
摘要
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 are considered. 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.