Doubly ionized states of carbon tetrafluoride

High resolution Auger-electron and double-charge-transfer spectroscopies have been used to investigate the doubly ionized states in CF₄. The double-charge-transfer spectra show that both the lowest singlet and triplet states in the CF₄ dication have an energy of 38.0±0.4 eV. Auger-electron spectroscopy gives information concerning higher energy states in the CF²⁺₄ ion. Peaks have been measured in the double ionization energy range 38-80 eV and have been assigned to the population of dication states using theoretically calculated spectra. Recent data from CF²⁺₄ fragmentation studies (Coding et al., J. Phys. B 24 (1991) 951) are discussed and correlated with the present work. The double-charge-transfer and Auger-electron spectra have been analyzed in terms of results obtained by two-particle Green's function calculations.