Transport and relaxation properties of isotopomeric hydrogen-helium binary mixtures. II. HD, D-2, T-2-He mixtures

The comprehensive comparison between calculated bulk non-equilibrium properties of hydrogen-helium isotopomeric mixtures and experiment that has previously been carried out for H-2-helium mixtures [2004, Molec. Phys., submitted] has been extended to mixtures of HD, D-2 and T-2 with He-3 and He-4. For HD-He-4 mixtures, comparison is also made, where possible, with previous calculations of Kohler and Schaefer [1983, Physica A, 120, 185]. The phenomena examined herein include low temperature interaction second virial coefficients, binary diffusion and thermal conductivity coefficients, rotational relaxation, transport property field effects and flow birefringence. Scattering calculations have been carried out for the HD-He PES of Schaefer and Kohler [1985, Physica A, 129, 469], and for both the Kohler-Schaefer and Tao [1994, J. chem. Phys., 100, 4947] potential surfaces for the D-2-He and T-2-He interactions. Comparisons between calculated and experimental results for HD, D-2, T-2-He mixtures confirm the conclusion, reached earlier from the H-2-He comparisons, that these potential surfaces are very close to the correct one for the hydrogen-helium interaction, and that the small differences between them cannot be distinguished readily by measurements of bulk gas phenomena unless the attendant experimental uncertainties are better than +/-0.3%.