Generalizing Rosenfeld's excess-entropy scaling to predict long-time diffusivity in dense fluids of Brownian particles: From hard to ultrasoft interactions

TL;DR

This paper extends Rosenfeld's excess-entropy scaling to predict long-time diffusivity in dense Brownian fluids with various interactions, successfully applying it to ultrasoft particles with anomalous density trends.

Contribution

It introduces a generalized Rosenfeld scaling method for Brownian dynamics, enabling accurate diffusivity predictions across different interaction potentials.

Findings

Predicts diffusivities within 20% accuracy for ultrasoft particles.

Demonstrates applicability to systems with anomalous density-dependent behavior.

Extends Rosenfeld's scaling from molecular to Brownian dynamics.

Abstract

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.