Calculated cross sections for transport coefficients of H 2 dilute in He and HI gas

Abstract

Relaxation cross sections determining transport coefficients of the binary systems He–H 2 and HI–H 2 have been calculated by using the Waldmann–Snider formalism of the linearized collision operator. After starting with the rotational relaxation times, which are determined by inelastic rotational transitions only, all the following contributions of relaxation cross sections to the binary transport coefficients of the viscosity, heat conductivity, and diffusion have been confined to the valid isotropic approximations, i.e. containing results of elastic collisions, which are only slightly corrected by inelastic effects. Cross sections of the pure gas components have not been done in this paper. The prepared input data have been differential cross sections of a sufficient number of energies and enough initial rotational j states of the molecules to produce converged results at temperatures from 5 K up to 1000 K. Convergence with regard to the contributed j states are shown in figures, the resulting numbers of the cross sections are printed in tables for temperatures up to 600 K. The results show almost identical cross sections for the ortho-H 2 and para-H 2 gas components in relaxation cross sections of purely translational motion, whereas cross sections pertaining purely internal rotational motion are significantly different for para-H 2 and ortho-H 2, and cross sections pertaining coupling of rotational–translational motion could be shown to be negligible as demonstrated in figures.