Kinetic Theory of Almost Classical Fluids

The Fokker–Planck equation with first-order quantum corrections in the weak coupling limit, which was derived by Davis, Hiroike, and Rice for the one-component fluid, is extended to mixtures. A rearrangement of terms believed negligible in the previous account leads to a more suitable form of the Fokker–Planck equation in which the friction tensor is an operator in momentum space. The equation is solved for the case of self-diffusion and numerical results are given. A 40% quantum correction to the soft-friction coefficient is predicted for liquid neon near the melting point, and a 4% correction is found for liquid argon at the corresponding temperature.