Vacuum ultraviolet negative photoion spectroscopy of dichlorodifluoromethane

摘要

Negative ions ~(35)Cl, ~(37)Cl, and F are observed in the vacuum ultraviolet photodissociations of dichlorodifluoromethane (CF _2Cl_2) using synchrotron radiation and their ion production efficiency curves are recorded in the photon energy range of 8.00 - 20.50 eV. Two similar spectra of the isotope anions ~(35)Cl and ~(37)Clshow that besides the strong bands related to the electron transitions from valence to Rydberg states converged to vertical ionization states, there are some additional peaks that can be assigned as the energetically accessible multi-body fragmentation processes, on the basis of the high-level G_3MP_2 calculations performed in this work and the thermochemistry data available in the literatures. The appearance energy of Cl is experimentally determined to be 8.20 ± 0.04 eV, in excellent agreement with the theoretical thermochemical value 8.19 eV. A novel competition between the ion-pair photodissociations to Cl and F anions is found in the photon energy range of 17.30-20.50 eV.