15min:

RENAT A. SULTANOV, DENNIS GUSTER, Business Computing Research Laboratory, St. Cloud State University, 31 Centennial Hall, 720 Fourth Avenue South, St. Cloud, MN 56301-4498.

Quantum-mechanical close-coupling calculations for rotational state resolved cross sections and thermal rate coefficients for the o-/p-H₂+HD collisions of astrophysical interest will be presented. Recently developed new global H₂-H₂ potential energy surface^a has been appropriately adopted for H₂ + HD and applied. The low temperature limit of o-/p-H₂+HD is investigated, which is of significant astrophysical interest in regard to the cooling of primordial gas and the interstellar media. A test of convergence and the results for cross sections with the new potential^a are obtained for a wide range of kinetic velocities including values down to 10 m/s. Sharp resonances have been reproduced in the cross sections of some transition states at very low energies.

Our results revealed^b, that for lower quantum transition states the new surface provides cross sections very close to those obtained in previous works, where the authors adopted some old potentials for H₂-H₂. However, for higher quantum states we found significant disagreements with previous results. Additionally, in our calculations new resonances are calculated in the 1300\pm 100 m/s region^b. The value of the resonances are relatively large, and it may exert a strong influence on the cooling processes in primodial gas and interstellar media.

^aA.I. Boothroyd, P. G. Martin, W. J. Keogh, M. J. Peterson, J. Chem. Phys., 116, 666 (2002).
^bR.A. Sultanov, D. Guster, Chem. Phys. Lett. 436, 19 (2007).