Dynamic signature for the equilibrium percolation threshold of attractive colloidal fluids

Short-time self-diffusivities, D(S)S, are computed for attractive colloidal fluids with van der Waals potentials to identify their percolation threshold and a previously unexplained dynamic transition. Our results show a discontinuous change in the slope of D(S)S vs temperature as the percolation threshold is crossed. Because D(S)S depends only on multibody hydrodynamic interactions, the percolation threshold of attractive colloidal fluids is shown to correspond to a transition in a dynamic property consistent with the linear viscoelastic measurements of Woutersen et al., J. Chem. Phys. 101, 542 (1994).