Reactions of CH3, CH3O, and CH3O2 radicals with O3

Ozone was photolyzed at 253.7 nm at 25 and -52 degrees in the presence of CH4 and O2 to measure the reactions of O3 with CH3, CH3O, and CH3O2. The O(1D) atoms produced in the primary photochemical act react with CH4 to give CH3 radicals which in turn can react with O2 to give CH3O2 and CH3O radicals. At very high O2 to O3 concentration ratios, the quantum yield of O3 disappearance approached 1.0, indicating that O3 reactions with CH3O2 and CH3O are slow. Upper limits to the rate coefficients at 25 degrees were computed. At lower values of the concentration ratio, chain decomposition of O3 occurred which could be explained by the reaction of O3 with CH3 radicals to produce CH2O, O2, and H atoms all the time. The two routes to these products are considered, and the preferred reaction channel is found.