The scaling behavior of the time-dependent diffusion coefficient D(t) in a suspension was studied by means of a molecular dynamics simulation. A visual collapse of the curves was obtained by suitable scaling of the time axis and vertical axis for D(t) at various concentrations. However, the derivatives of D(t) did not exhibit such a scaling behavior. By analyzing the kinetic regime in this simulation, it was concluded that the absence of scaling was due to the fact that the dynamics was not completely dominated by hydrodynamics processes. This provided further evidence on the purely hydrodynamic origin of the scaling behavior.

Scaling of the Time-Dependent Diffusion Coefficient by Molecular Dynamics Simulation. Zúñiga, I., Español, P.: Physical Review Letters, 1993, 71[22], 3665-8