New insights into the kinetics of the reaction of vinyl radical with Nitrogen dioxide

Abstract

The kinetics of the reactions of vinyl radical with NO2 have been investigated by ab initio kinetics calculations. The potential energy profile is constructed at the CCSD(T)-F12a/aVTZ-F12//M06-2X/aug-cc-pVDZ level of theory. Micro-canonical variational transition state theory and Rice-Ramsperger-Kassel-Marcus/Master Equation calculations were performed to obtain temperature- and pressure-dependent rate coefficients. The reaction of vinyl radical and NO2 can start from an attack of the vinyl radical on the N-atom or O-atom site of NO2, followed by a number of competing reaction pathways (rearrangement and decompositions of nitro or nitrite intermediate). The bimolecular product channel generating NO + CH2CHO was found to be the most favorable. Additionally, for the NO release, both the barrier-less process and the pathway via a saddle point are identified in this study. The proposed reaction pathways and calculated rate coefficients were incorporated into a kinetic model. The results illustrate that the present calculation remarkably affects the model performance in terms of predicting species evolution. After incorporating the new Ċ2H3 + NO2 kinetics, the predictions of species evolution are in reasonable agreement with the experimental measurements.