A close-coupling study of vibrational-rotational quenching of CO by collision with hydrogen atoms

Quantum-mechanical scattering calculations were performed for the rovibrational relaxation of CO in collisions with H atoms using the close-coupling approach for collision energies between 10(-6) and 1500 cm(-1). We adopted the H-CO interaction potential of Werner, Keller, and Schinke and computed the state-to-state and total cross sections for the quenching of the upsilon=1, j=0-2 levels of CO. Numerous resonances, as a consequence of the van der Waals potential, are observed and the cross sections are found to approach the Wigner limit at low energies. Also, by averaging the cross sections over a Boltzmann distribution of velocities of the incoming atom, quenching rate coefficients are obtained and found to be consistent with previous infinite-order sudden approximation calculations for temperatures between 100 and 300 K. (C) 2005 American Institute of Physics.