title: Temperature and Pressure-Dependent Rate Coefficients for the Reaction of Vinyl Radical with Molecular Oxygen.
abstract: State-of-the-art calculations of the C2H3O2 potential energy surface are presented. A new method is described for computing the interaction potential for R + O2 reactions. The method, which combines accurate determination of the quartet potential along the doublet minimum energy path with multireference calculations of the doublet/quartet splitting, decreases the uncertainty in the doublet potential and thence the rate constants by more than a factor of 2. The temperature- and pressure-dependent rate coefficients are computed using variable reaction coordinate transition-state theory, variational transition-state theory, and conventional transition-state theory, as implemented in a new RRKM/ME code. The main bimolecular product channels are CH2O + HCO at lower temperatures and CH2CHO + O at higher temperatures. Above 10 atm, the collisional stabilization of CH2CHOO directly competes with these two product channels. CH2CHOO decomposes primarily to CH2O + HCO. The next two most significant bimolecular products are OCHCHO + H and (3)CHCHO + OH, and not C2H2 + HO2. C2H3 + O2 will be predominantly chain branching above 1700 K. Uncertainty analysis is presented for the two most important transition states. The uncertainties in these two barrier heights result in a significant uncertainty in the temperature at which CH2CHO + O overtakes all other product channels.
authors.affiliation: †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.|‡School of Engineering, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: C Franklin
authors.initials: CF
authors.lastname: Goldsmith
authors.affiliation: †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Lawrence B
authors.initials: LB
authors.lastname: Harding
authors.affiliation: †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Georgievskii
authors.affiliation: †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: Miller
authors.affiliation: †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Klippenstein