Ab initio and direct dynamics study on the hydrogen abstraction reaction C2H3+HCHO

We present an ab initio direct dynamics study of thermal rate constants of the hydrogen abstraction reaction of C2H3 + HCHO --> C2H4 + CHO. The MP2/cc-pVDZ method is employed to optimize the geometries of stationary points as well as the points on the minimum energy path (MEP). The energies of all the points were further refined at the QCISD(T)/cc-pVTZ level of theory. The rate constants were evaluated using canonical variational transition state theory (CVT) and canonical variational transition state theory with small-curvature tunneling contributions (CVT/SCT) in the temperature range of 300 2500 K. The calculated results show that the rate constants have positive temperature dependence in the calculated temperature range. The calculated rate constants at the QCISD(T)/cc-pVTZ//MP2/cc-pVDZ level of theory are in good agreement with available literature data. (C) 2004 Elsevier B.V. All rights reserved.