DIFFUSION IN LIQUID AND SOLID-SOLUTIONS HE-3-HE-4

An exact expression for diffusion time, which depends on the interacti on rates for particles of not only different, but also of the same spe cies, has been derived from the system of kinetic equations. The resul t is valid for particles with arbitrary statistics and energy-momentum relations. The derived general relations are valid for investigating diffusion in liquid and solid He-3-He-4 mixtures. The contribution of interaction between quasiparticles of the same type to the diffusion c oefficient and effective thermal conductivity of superfluid solutions is analyzed. The calculated values are compared with experimental data , The calculated diffusion coefficient of He-3-He-4 solid solutions di ffers from the previous theoretical results. A comparison of the obtai ned diffusion coefficient with experimental data makes it possible to determine the numerical value of the energy band width for impurity qu asiparticles. (C) 1997 American Institute of Physics.