A theoretical treatment for the kinetics of vinyl radical (C_2H_3) with molecular oxygen is presented. The C_2H_3O_2 potential energy surface (PES) was computed using high-level ab initio methods, with accuracy comparable to HEAT, W4, or focal-point calculations. The vinyl + O_2 interaction potential was computed using multi-reference configuration interaction and multi-reference perturbation theory (with six electrons in four orbitals for O_2 and three electrons in three orbitals for C_2H_3), 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 + CH_2O. 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.
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