Core-valence double photoionization of the CS2 molecule

Double photoionization spectra of the ${\text{CS}}_2$ molecule have been recorded using the TOF-PEPECO technique in combination with synchrotron radiation at the photon energies $h\nu =220$ , 230, 240, 243, and 362.7 eV. The spectra were recorded in the S 2p and C 1s inner-shell ionization regions and reflect dicationic states formed out of one inner-shell vacancy and one vacancy in the valence region. MCSCF calculations were performed to model the energies of the dicationic states. The spectra associated with a S 2p vacancy are well structured and have been interpreted in some detail by comparison to conventional S 2p and valence photoelectron spectra. The lowest inner-shell-valence dicationic state is observed at the vertical double ionization energy 188.45 eV and is associated with a ${\left(2{\text{p}}_{3/2}\right)}^{-1}{\left(2{\pi }_g\right)}^{-1}$ double vacancy. The spectrum connected to the C 1s vacancy shows a distinct line at 310.8 eV, accompanied by additional broad features at higher double ionization energies. This line is associated with a ${\left(\text{C}1\text{s}\right)}^{-1}{\left(2{\pi }_g\right)}^{-1}$ double vacancy.