Limiting high-pressure rate coefficient for the recombination reaction FSO2 + FSO3 → FS(O2)O(O2)SF: An experimental and theoretical study

The kinetics of the recombination reaction FSO2 + FSO3 → FS(O2)O(O2)SF has been studied at 298 K. Both radicals were generated by 193-nm laser flash photolysis of FS(O2)O(O2)SF at total CO pressures ranging from 130 to 800 mbar. The decay of FSO3 radical was monitored by absorption spectroscopy at 450 nm. In all conditions, the reaction was found to be very close to the second-order regime being the limiting high-pressure rate coefficient (6.5 ± 1.1) × 10−11 cm3 molecule−1 s−1. This value agrees very well with 7.7 × 10−11 cm3 molecule−1 s−1, as derived from statistical adiabatic channel model/classical trajectory calculations on an electronic potential obtained from density functional theory calculations.