Cubic Cell Model for Self-Diffusion in Liquids

Abstract

A cubic cell model for viscous flow and self‐diffusion in liquids has been developed such that a linear Langevin equation for condensed systems can be deduced directly from the corresponding Navier‐Stokes equation, the molecular friction coefficient being then related to the viscosity and cell size. On restricting interactions to nearest neighbors in cubic symmetry involving an arbitrary choice of the number of nearest molecules and linking the friction coefficient and diffusivity by stochastic considerations, an expression has been produced that predicts self‐diffusion coefficients from viscosity and density data with an average deviation of 9%.