Rotational energy transfer in H2 + H2

Quantum-mechanical close-coupling calculations for state-to-state cross-sections and thermal rate coefficients are reported for H2 + H2 collisions. Two recently developed potential energy surfaces (PESs) for the H2–H2 system are applied, namely, the global potential surface from the work [A.I. Boothroyd et al., J. Chem. Phys. 116 (2002) 666], and a restricted, model surface from the work [P. Diep and J.K. Johnson, J. Chem. Phys. 113 (2000) 3480; P. Diep, J.K. Johnson, J. Chem. Phys. 112 (2000) 4465]. The low temperature limit is investigated. We found significant differences in cross-sections and corresponding thermal rate coefficients calculated with these two PESs.