  Computer simulations are used to test whether a recently introduced
generalization of Rosenfeld's excess-entropy scaling method for estimating
transport coefficients in systems obeying molecular dynamics can be extended to
predict long-time diffusivities in fluids of particles undergoing Brownian
dynamics in the absence of interparticle hydrodynamic forces. Model fluids with
inverse-power-law, Gaussian-core, and Hertzian pair interactions are
considered. Within the generalized Rosenfeld scaling method, long-time
diffusivities of ultrasoft Gaussian-core and Hertzian particle fluids, which
display anomalous trends with increasing density, are predicted (to within 20%)
based on knowledge of interparticle interactions, excess entropy, and scaling
behavior of simpler inverse-power-law fluids.
