Quantum degeneracy effect on gas diffusion

Abstract

In this work, the self-diffusion coefficients of Fermi/Bose gases are considered for both hydrodynamic and free molecular transport regimes and the both regime’s diffusion coefficients are expressed in a single relation including Knudsen number and quantum degeneracy. This relation also gives information about the transitional behavior of the diffusion coefficient between two regimes. Furthermore, the variations of diffusion coefficients with quantum degeneracy and Knudsen number are analyzed in detail. By using the series expansions of Polylogarithm functions, more simple and useful diffusion coefficient expressions are obtained for strongly and weakly degeneracy conditions.