Close-coupled calculations of viscosity transport-relaxation cross sections for HD-He: Comparison with experiment

Exact closed-coupled scattering calculations have been performed for the system HD-He employing the H2-He potential obtained by Shafer and Gordon transformed to allow for the shift in the centre of mass for HD. The decay and production effective cross sections related to the viscomagnetic effect for the system HD at infinite dilution in a bath of He atoms have been computed and comparisons made with the corresponding values obtained experimentally at 77.3 K and 293 K. Excellent agreement is obtained for all cross sections at 77.3 K and all cross sections except G at 293 K. The relatively poorer agreement for G at 293 K is largely due the inclusion of insufficient j-levels in the cross section matrix. It is confirmed by the present calculation that both the pure angular momentum tensor polarization, JJ/[J2(J2−24)]12, and the one responsible for the collision broadening of the depolarized Rayleigh (DPR) light scattering spectrum, JJ/(J2−24), are different from the polarization governing the viscomagnetic effect.