Mechanism of the atomic oxygen(3P) + hydrogen sulfide reaction. Abstraction or addition?

The question of whether the reaction of O(/sup 3/P) with H/sub 2/S proceeds by abstraction O + H/sub 2/S ..-->.. OH + SH, or by addition, O + H/sub 2/S ..-->.. (H/sub 2/SO)* ..-->.. products, was investigated by quantitative gas chromatographic analysis of N/sub 2/ and CO/sub 2/ produced in mercury-photosensitized mixtures of N/sub 2/O, H/sub 2/S, and CO. Reactant pressures were chosen so that less than 5% of the O atoms formed from N/sub 2/O would react with CO, but a large fraction of any OH radicals formed from reaction of O with H/sub 2/S would react with CO to form CO/sub 2/. The CO/sub 2/ yields were compared with those calculated from an expression derived by steady-state treatment of a simple mechanism. The CO/sub 2/ yields indicated that 52% of the O + H/sub 2/S reaction proceeds by abstraction, although it could be as much as 100% depending on the extent of H/sub 2/S/sub 2/ formation by SH radical recombination and the rate constant for the reaction of O atoms with H/sub 2/S/sub 2/. 3 figures, 3 tables.