The electronic spectrum, photodecomposition and dissociative electron attachment of CF 2Cl 2: An ab initio configuration interaction study

Abstract

MRD—CI calculations are carried out for chlorofluoromethane in a number of electronic states. The electronic spectrum up to 9 eV is characterized by intra-valence shell transitions from the chlorine lone pairs into antibonding σ*-type orbitals. The first Rydberg state is calculated to occur around 9.2 eV. The calculated first four ionization potentials are in good agreement with corresponding measured values and can be assigned to single-orbital ionization of chlorine lone-pair combinations. The potential energy curves for chlorine removal have also been calculated for the ground and first excited states in order to obtain more insight into the photodecomposition and chlorine atom release; similarly potential energy curves as a function of the CF 2Cl 2 separation are calculated in order to investigate photodecomposition into CF 2 in various electronic states. Finally, the potential energy curve as a function of the CCl separation is calculated for the negative ion; the dissociation of CF 2Cl 2 in its ground state into Cl − and CF 2Cl by slow electrons is supported essentially quantitatively by the present calculations.