Theoretical Study on the Kinetic and Mechanism of H+HO2 Reaction

The kinetics and mechanism of reaction of a hydroperoxyl radical (HO 2 ) with a hydrogen atom on both singlet and triplet surfaces were studied by employing DFT, CCSD, and G3 methods along with the Aug-cc-pVTZ basis set. MC-SCF and CCD methods were used to explore potential energy surfaces. Major end products from different channels were H 2 O + O, H 2 + O 2 , and OH. Formation of chemically activated hydrogen peroxide HOOH was the most exothermic path in this system that dissociates to the ground state OH( 2 Π) radicals. Another energized transient species was water oxide H 2 OO, which has local minimum on the singlet potential-energy surface. The energized water oxide rapidly isomerized to hydrogen peroxide HOOH or dissociated to H 2 Ο + Ο( 1 D). Transition state theory and RRKM theory were used to calculate the rate constants for different channels.