Vacuum ultraviolet negative photoion spectroscopy of dichlorodifluoromethane

► Photolysis of freon molecules is closely related to the destructions of atmosphere. Negative ions 35Cl̄, 37Cl̄, and F̄ are observed in the vacuum ultraviolet photodissociations of CF2Cl2 using synchrotron radiation and their ion production efficiency curves are recorded in the photon energy range of 8.00-20.50 eV. The appearance energy of Cl̄ 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 Cl̄ and F̄ anions is found in the photon energy range of 17.30-20.50 eV.