Computational study on the mechanism and kinetics for the reaction between HO and -propyl peroxy radical.

The -propyl peroxy radical (-CHO) is the key intermediate during atmospheric oxidation of propane (CH) which plays an important role in the carbon and nitrogen cycles in the troposphere. In this paper, a comprehensive theoretical study on the reaction mechanism and kinetics of the reaction between HO and -CHO was performed at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-311G(d,p) level of theory. Computational results show that the HO + -CHO reaction proceeds on both singlet and triplet potential energy surfaces (PESs). From an energetic point of view, the formation of CHOH and O triplet hydrogen abstraction is the most favorable channel while other product channels are negligible. In addition, the calculated rate constants for the title reaction over the temperature range of 238-398 K were calculated by the multiconformer transition state theory (MC-TST), and the calculated rate constants show a negative temperature dependence. The contributions of the other four reaction channels to the total rate constant are negligible.