Transport and relaxation cross-sections for He-N₂mixtures

Classical-trajectory calculations are reported using two recent potentialenergy surfaces—the theoretical surface of Bowers et al. and the multiproperty fit of Gianturco et al. Comparisons with measurements of diffusion, viscosity, thermal conductivity, rotational relaxation, depolarized Rayleigh light scattering and magnetic-field effects on diffusion, viscosity and thermal conductivity show generally better agreement than obtained using the earlier (HFD1) surface of Fuchs et al., but some differences remain. Overall the surface of Bowers et al. is more reliable but it tends to be insufficiently anisotropic. Results using the infinite-order-sudden approximation are compared with the classical-trajectory results where possible. While errors in the traditional transport properties are small (<2%), errors in properties directly related to the anisotropy are much larger and can exceed 40% for the viscomagnetic-effect relaxation cross-section.