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

Abstract The kinetics of the recombination reaction FSO 2  + FSO 3  → FS(O 2 )O(O 2 )SF has been studied at 298 K. Both radicals were generated by 193-nm laser flash photolysis of FS(O 2 )O(O 2 )SF at total CO pressures ranging from 130 to 800 mbar. The decay of FSO 3 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  cm 3  molecule −1  s −1 . This value agrees very well with 7.7 × 10 −11  cm 3  molecule −1  s −1 , as derived from statistical adiabatic channel model/classical trajectory calculations on an electronic potential obtained from density functional theory calculations.