The effect of collision energy and vibrational excitation on the reaction of C2H+2+H2

Abstract

The relative efficiencies between the excitation of C–C stretching vibration and collision energy on the promotion of the H atom transfer reaction of C2H+2 +H2→C2H+3 +H have been examined. At low collision energies the reaction is strongly vibrationally enhanced in agreement with previous thermal energy studies. Translational energy was found to be not as effective as exciting the C–C stretching vibration in promoting the reaction. The results indicate that the H atom transfer from H2 to the C atom should have a late barrier, but the C–C stretching vibration of C2H+2 is apparently coupled to the reaction coordinate. Because the C–C bond in C2H+3 is expected to be longer than that of C2H+2, vibrational energy added to the C–C bond might reduce the barrier for H atom transfer from H2 to a C atom in C2H+2.