Transport coefficients of multicomponent mixtures of noble gases based on ab initio potentials: Diffusion coefficients and thermal diffusion factors

Abstract

Diffusion coefficients and thermal diffusion factors of binary, ternary, and quaternary mixtures of helium, neon, argon, and krypton at low density are computed for wide ranges of temperatures and molar fractions, applying the Chapman–Enskog method. Two definitions of the diffusion coefficients are discussed, and a general relation between them is obtained. Ab initio interatomic potentials are employed in order to calculate the omega-integrals being part of the expression of the reported quantities. The relative numerical errors of the diffusion coefficients do not exceed the value of 5 × 10−5 being even smaller in some cases. The uncertainties of diffusion coefficients due to the interatomic potential vary between 4 × 10−4 and 6 × 10−3. The numerical error and uncertainty due to the potential of the thermal diffusion factors are estimated as 10−4 and 3 × 10−3, respectively. It is shown that the present results for binary mixtures are more accurate than any other available in the literature, while the results for ternary and quaternary mixtures are reported for the first time.