Deactivation of vibrationally excited ozone by O( 3P) atoms

Using laser-induced fluorescence of ozone (to measure the rate of disappearance of O ₃^†) and NO ₂ titration (to determine O atom concentrations), we have determined bimolecular rate constants for the deactivation by O( ³P atoms) of ozone in excited stretching and bending modes. These experiments do not distinguish between deactivation by (a) the exchange of vibrational and translational energy or (b) the chemical reaction O ₃ + O → 2O ₂. If the non-reactive pathway (a) is assumed to dominate, then O( ³P) is 150 times more effective than O ₂ in deactivating O ^†₃. If chemical reaction (b) is dominant, the bimolecular rate constant for O ^†₃ + O( ³P) is larger by a factor of 150-1500 than that for ground-state ozone.