Modeling diffusion in colloidal suspensions by dynamical density functional theory using fundamental measure theory of hard spheres

We study the dynamics of colloidal suspensions of hard spheres that are subject to Brownian motion in the overdamped limit. We obtain the time evolution of the self and distinct parts of the van Hove function by means of dynamical density functional theory (DDFT). The free energy model for the hard sphere fluid that we use is the very accurate White Bear II version of Rosenfeld's fundamental measure theory. However, in order to remove interactions within the self part of the van Hove function a non-trivial modification has to be applied to the free energy functional. We compare our theoretical results with data that we obtain from dynamical Monte Carlo simulations and find that the latter are well described by our approach even for colloid packing fractions as large as 40%.