Threshold energy and excitation function for the reaction of atomic hydrogen with cyclohexane

Abstract

The reaction of photochemically generated hydrogen atoms with [²H₁₂]cyclohexane has been examined and the integral reaction probability of the abstraction reaction (1) determined at different translational energies of H*: H*+ C₆D₁₂→ HD + C₆D₁₁. (1) The phenomenological threshold energy of reaction (1) is 39 ± 4 kJ mol^–1. Measurements of the moderating effect of xenon at different intial translational energies of H* have been combined with calculated collision densities to obtain the excitation function for reaction (1) in the energy range 30–200 kJ mol^–1. The maximum reaction cross-section per D atom in this range is markedly less than that for the corresponding reaction of H* with the secondary D in n-C₄D₁₀.