An angle resolved electron–ion recoil vector correlation study of alternate ion dissociation channels in à CF3I+

Abstract

Electron–ion recoil vector correlations are examined for the ionization and subsequent dissociation of à state CF₃I⁺. The magnitude of the electron and fragment ion recoil vectors permits the energetics of two alternative decays to I⁺ and CF₃⁺ to be compared, while differences between the angular correlations are interpreted as molecule-frame photoelectron angular distributions which, in the I⁺ channel, are smeared by molecular rotation between ionization and dissociation. Quantitative estimates of sub-ps I⁺ decay lifetimes are extracted, indicating very different decay rates for the alternative dissociation channels. Surprisingly, the ka₁ and ke photoelectron continua exchange polarization dependence in the I⁺ channel correlations and vibronic interactions are postulated in explanation. This can also rationalize the non-adiabatic à CF₃I⁺→I⁺ decay mechanism and the branching competition between the CF₃⁺ and I⁺ channels.