A theoretical study of the kinetics of C2H3+H

Abstract

High level quantum chemical simulations of the interaction of vinyl radical with H are implemented in transition state theory based calculations of the reaction kinetics. The quantum chemical simulations, performed at the CAS+1+2 level, indicate the presence of three separate barrier-less channels; two for addition and one for abstraction. A variable reaction coordinate approach is employed in the determination of transition state partition functions for each of these channels. The optimized transition state dividing surfaces are found to be qualitatively similar to the contours of the radical molecular orbital for vinyl. The temperature and pressure dependence for the overall reaction kinetics is analyzed on the basis of a one dimensional master equation implementing the transition state theory estimates for the energy resolved rate constants. The resulting theoretical estimates for the total rate constants and for the branching between addition, elimination and abstraction are compared with the available experimental data.