Theoretical investigations of the quenching of CO fluorescence by ortho and para H-2

A simple theory for near resonance vibrational-rotational energy transfer is developed and applied to the vibrational fluorescence experiments for the relaxation of CO in the presence of ortho- and para-H-2. The kinetic data for ortho-H-2 is readily interpreted with an extended Landau-Teller plot, whereas the low temperature deviation of the CO relaxation with para-H-2 is attributed to the near resonant transition CO(nu = 1) + Pi(2)(j = 2) -> CO(nu = 0) + H-2(j = 6) + Delta E = 88 cm(-1). The extracted thermally averaged cross section for this particular process behaves roughly like I I which is interpreted in terms of a simple anisotropic perturbation. At low temperatures (near liquid nitrogen) the ortho-para deviation should cease primarily due to the depletion or the j = 2 state.