School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia

摘要

We used dynamic light scattering (DLS) and computer simulations based on the fluctuating lattice Boltzmann equation (LBE) method to study the short-time Brownian dynamics of colloidal particles that interact like hard spheres. The dynamics are characterized by a Q-vector-dependent diffusion coefficient DS(Q). Using DLS, we have mesaured DS(Q) in the vicinity of the main (first) peak in the structure factor S(Q) for samples of poly-methylmethacrylate particles at volume fractions phi ranging from dilute up to the disorder-order transition (i.e., crystallization at phi =0.494). In addition we have determined the short-time self-diffusion (DSS) and collective-diffusion DCS coefficients. We have extracted the same quantities from simulations of equilibrium configurations of hard spheres using a fluctuating lattice Boltzmann equation method for the fluid phase coupled to Newtonian mechanics for the colloidal particles. For all samples studied, close quantitative agreement is found between the results of the DLS experiments and the LBE simulations.