A theoretical study of energy transfer in the quenching of O(¹D₂) by CO(¹Σ⁺)

Abstract

Energy transfer processes occurring during the collisional quenching of O(¹ D) by CO(¹Σ⁺) are studied using a classical collision complex model together with potentials previously derived for the C(³ P) + O₂(³Σ _g ^-) reaction. Room temperature quenching rate constants, electronic-vibrational transfer efficiencies and product vibrational state distributions are in good agreement with experiment. The calculated and experimental temperature dependences of the electronic-vibrational transfer efficiencies and vibrational populations, however, disagree. The effect of using vibrationally excited CO as a quenching partner is studied and shown to result in a lowering of the quenching rate constant by a factor of 4 at room temperature. Enhancement of initial translational energy by the equivalent of a vibrational quantum of energy leads to an even larger decrease in the rate constant. This difference between vibrational and translational energy enhancement is interpreted in terms of an increased centrifugal barrier in the latter case.