The effect of the torsional and stretching vibrations of C2H6 on the H+C2H6 - H-2+C2H5 reaction

摘要

We present a three-dimensional quantum scattering model to treat reactions of the type H+C2H6-> H-2+C2H5. The model allows the torsional and the stretching degrees of freedom to be treated explicitly. Zero-point energies of the remaining modes are taken into account in electronic structure calculations. An analytical potential-energy surface was developed from a minimal number of ab initio geometry evaluations using the CCSD(T,full)/cc-pVTZ//MP2(full)/cc-pVTZ level of theory. The reaction is endothermic by 1.5 kcal mol(-1) and exhibits a vibrationally adiabatic barrier of 12.0 kcal mol(-1). The results show that the torsional mode influences reactivity when coupled with the vibrational C-H stretching mode. We also found that ethyl radical products are formed internally excited in the torsional mode. (C) 2005 American Institute of Physics.