Rovibrational excitation of¹²C¹⁶O by para-H₂

Cross sections for the rovibrational excitation of 12 C 16 O by para-H 2 , constrained to its ground state, have been computed. A quantum mechanical close-coupling formalism has been employed, the rotational motion of the CO molecule being treated within the infinite-order sudden (IOS) or breathing-sphere (BS) approximation. Satisfactory agreement is obtained with the semiclassical calculations of Poulsen and Billing (1982). Allowing for remaining uncertainties in the potential, the authors' results are also in reasonable accord with experimental measurements of the n=1 to n=0 vibrational relaxation coefficient. Discrepancies are found with recent quantal calculations by Drolshagen and Gianturco (1983).