Close-coupling calculations of rotational energy transfer in p-H2 + HD

We report quantum-mechanical close-coupling calculations for rotational state resolved cross-sections for p-H2 + HD collisions. The low temperature limit of p-H2 + HD is investigated, which is of significant astrophysical interest in regard to the cooling of primordial gas and the interstellar media. Sharp resonances have been reproduced in the cross-sections of some transition states at very low kinetic energies, Ekin ∼ (10−4–10−5) eV.