BROWNIAN DYNAMICS SIMULATIONS OF SELF AND COLLECTIVE DIFFUSION OF NEAR HARD-SPHERE COLLOIDAL LIQUIDS - INCLUSION OF MANY-BODY HYDRODYNAMICS

Ermak's 1975 Brownian dynamics free-draining algorithm is extended to include the coarse grained effects of many-body hydrodynamics, using a local density approximation for the friction coefficient. The model r eproduces the long term self-diffusion coefficients of model near hard sphere colloidal liquids within the experimental uncertainty over the complete solid volume fraction range. The local structural relaxation , manifested in the force autocorrelation functions, is slowed down up on the introduction of mean-field hydrodynamics. This effect is also e vident in the collective diffusion coefficients, which show an enhance d relative slowing down compared with the free-draining model at wavev ectors k similar to 2 pi/sigma.