Theoretical treatment of quenching in O(1D) + N2 collisions

It is maintained that quenching of O(1D) by collision with N2 proceeds by formation of a collision complex on the lowest singlet potential surface. Once a collision complex is formed, even the weak spin−orbit interaction in O atom can induce quenching with essentially unit probability (at thermal energies) because the intersection of the singlet [O(1D) + N2] and triplet [O(3P) + N2] potential surfaces is crossed many times during the life of the complex. Rather crude, but qualitatively reasonable potential surfaces for O(1D) + N2 are constructed and classical trajectory calculations carried out to show that the cross section for complex formation is indeed appreciable, ∼40 Å2 at thermal energy; a statistical model is used to determine the quenching probability of the collision complex. Values obtained for the magnitude of the thermal rate constant for quenching, and the fraction of the exoergicity which appears as vibrational excitation of N2, are both in good agreement with experimental results.