PHOTOELECTRON-PHOTOION COINCIDENCE STUDY OF VINYLFLUORIDE

Photoelectron-photoion coincidence spectroscopy is used to study the ionic fragmentation reactions of energy-selected vinylfluoride molecular cations. The experimental appearance potentials for the dominant fragment ions are in good agreement with literature data. An appearance potential of 14.5 ± 0.1 eV was obtained for the CF+ fragment ion, which is about 1 eV lower than an older electron impact value. The energy dependence of the rate constant of the HF elimination reaction was determined near threshold and used to explain the observed kinetic shift. Ionization from a fluorine lone-pair type orbital, generating the state C̃(2A″), leads to a preferential, non-statistical fragmentation into C2H3+ and F. © 1979.