Self-diffusion in dense 2-dimensional liquids, consisting of mixtures of soft disks, was studied by using constant-temperature constant-pressure molecular dynamics simulations. At low solute concentrations, both the solute and solvent diffusion coefficients were found to exhibit a non-monotonic dependence upon the solute disc diameter. An anomalously high diffusivity of the solute was shown to arise from disruption of the local solvent structure and from the resultant increase in the solvent mobility.

Solute-Enhanced Diffusion in a Dense Two-Dimensional Liquid D.N.Perera, P.Harrowell: Physical Review Letters, 1998, 80[20], 4446-9