Inner Shell Ionization and Excitation of CCl4 and its Relation to Electron Scattering

The fragmentation of the tetrachloromethane molecule, following core-shell photoexcitation and photoionization in the neighborhood of the chlorine K-edge has been studied by using time-of-flight mass spectroscopy and monochromatic synchrotron radiation. Branching ratios for ionic dissociation were derived for all detected ions, which are informative of the decay dynamics and photofragmentation patterns of the core-excited species. In addition, the absorption yield has been measured, with a new assignment of the spectral features. The structure that appears above the Cl 1s ionization potential in the photoionization spectrum, has been ascribed in terms of the existing connection with electron-CCl4 scattering through experimental data and calculations for low-energy electron-molecule cross sections. In addition, the production of the doubly ionized Cl2+ as a function of the photon energy has been analysed in terms of a simple and appealing physical picture, the half-collision model. PACS numbers: 33.80.-b, 33.80.Eh

Keywords: Photofragmentation, Ion branching ratios, Deep core, Ionization, Photoionization, CCl4, Tetrachloromethane, Synchrotron radiation, Chlorine Kedge, Cl 1s, Photoabsorption, X-rays.