Scaling of the time-dependent diffusion coefficient by molecular dynamics simulation

The scaling behavior of the time-dependent diffusion coefficient D(t) in a suspension is studied by means of a molecular dynamics simulation. We obtain a visual collapse of the curves by suitable scaling of time axis and vertical axis for D(t) at different concentrations. However, the derivatives of D(t) do not show such a scaling behavior. By analyzing the kinetic regime probed in this simulation we conclude that the absence of scaling is due to the fact that the dynamics is not completely dominated by hydrodynamics processes. This provides further evidence on the purely hydrodynamic origin of the scaling behavior.