Quantum mechanical rate constants for H+O2 ⇆ O+OH and H+O2 → HO2 reactions

Canonical rate constants for both the forward and reverse H + O-2 <-> O + OH reactions were calculated using a quantum wave packet-based statistical model on the DMBE IV potential energy surface of Varandas and co-workers. For these bimolecular reactions, the results show reasonably good agreement with available experimental and theoretical data up to 1500 K. In addition, the capture rate for the H + O-2 -> HO2 addition reaction at the high-pressure limit was obtained on the same potential using a time-independent quantum capture method. Excellent agreement with experimental and quasi-classical trajectory results was obtained except for at very low temperatures, where a reaction threshold was found and attributed to the centrifugal barrier of the orbital motion.