Hartley–Crank equation and standard velocity correlation coefficients

Abstract

If velocity correlation coefficients as defined by Hertz take the ‘standard’ values said to be characteristic of a non-interacting mixture, the interdiffusion coefficient is related to the composition of the mixture by the well-known Hartley–Crank equation. The assumptions which underlie the definitions of standard velocity correlation coefficients must therefore be consistent with those on which the Hartley–Crank equation is based.