Close-Coupling Studies of Rotational Excitation in H-H2Collisions

Close-coupling calculations are reported for low-energy H-${\mathrm{H}}_2$ collisions. These results are compared with Tang's distorted-wave calculations of the differential and total cross sections for the $j=0\mathrm{}$ to $j=2\mathrm{}$ rotational transition. The close-coupling results for the total cross section are found to agree quantitatively with the distorted-wave results. Furthermore, the relative transition probabilities for various partial waves determined by Tang agree qualitatively with the close-coupling results reported here. The strong forward peaking in the cross section $\sigma \left(\theta \right)$ reported by Tang is also found in the present study. However, there appear to be significant differences in the magnitudes and positions of oscillations in the differential cross sections as determined by the close-coupling and distorted-wave methods. Finally, close-coupling results for the $j=0\mathrm{}$ elastic scattering differential cross section are presented and discussed briefly.