(271g) Temperature and Pressure Dependent Rate Coefficients for the Reaction of Vinyl Radical With Molecular Oxygen

A theoretical treatment for the kinetics of vinyl radical (C₂H₃) with molecular oxygen is presented.  The C₂H₃O₂ potential energy surface (PES) was computed using high-level ab initio methods, with accuracy comparable to HEAT, W4, or focal-point calculations.  The vinyl + O₂ interaction potential was computed using multi-reference configuration interaction and multi-reference perturbation theory (with six electrons in four orbitals for O₂ and three electrons in three orbitals for C₂H₃), and the corresponding capture rate was computed using variable reaction coordinate transition state theory (VRC-TST).  Additional multi-reference calculations were performed for several transition states, including the decomposition of vinylperoxy to form vinoxy + O and the isomerization of dioxiranylmethyl to oxiranyloxy, which are critical to the overall branching between the two dominant product channels, vinoxy + O and HCO + CH₂O.  Temperature and pressure-dependent rate constants are computed by solving the Master Equation.  A double-exponential-down model is used to describe the effects of super-colliders in collisional energy transfer.