INFRARED MULTIPLE-PHOTON DISSOCIATION OF THE ACETONE ENOL RADICAL-CATION - DEPENDENCE OF NONSTATISTICAL DISSOCIATION ON INTERNAL ENERGY

Infrared multiple-photon dissociation experiments were used to study t he energy dependence of the nonstatistical dissociation of the acetone enol cation. This ion isomerizes to the acetone cation, which then lo ses its methyl groups at unequal rates. We show that the nonstatistica l dissociation increases significantly with the energy in excess of th e isomerization barrier. The implication is that excitation of a mode (other than the reaction coordinate), in the transition state for isom erization of the acetone enol cation to the acetone cation, affects th e amount of nonstatistical reaction.