Kinetic energy release distributions in the dissociation of CH +4 and CD +4 ions

Abstract

The release of translational energy in the dissociation of energy-selected CH⁺₄ and CD⁺₄ ions is measured by a photoelectron–photoion coincidence experiment. Loss of H and D, respectively, are the principal reactions observed; detailed kinetic energy distributions accompanying the formation of CH⁺₃ and CD⁺₃ are obtained. The surprisal content of these distributions is found to be identical at all ionization energies observed and for both isotopes. A statistical model of the dissociations is considered to be appropriate and a number of calculations are performed. It is found that the use of the Langevin model to describe the effects of the centrifugal barrier to dissociation does not give exact quantitative agreement with the experimental results and this deficiency is examined.