Experimental and theoretical study of the recombination reaction FSO2 + O2 → FS(O2)OO

The kinetics of the recombination reaction FSO2 + O2 → FS(O2)OO (1) has been studied at 298 K. FSO2 together with FSO3 radicals were generated by 193 nm laser flash photolysis of FS(O2)O(O2)SF. The measured rate coefficient at one atmosphere total pressure is k1 = (4.6 ± 0.6) × 10−15 cm3 molecule−1 s−1. Molecular properties for the FS(O2)OO radical were calculated at the B3LYP/6-311+G(3df) and CCSD/6-311G(d) levels of theory. Consistent with the measured k1 value, different density functional theory and Gaussian-3 calculations predict an electronic energy barrier for reaction (1) close to 3 kcal mol−1.