Fragmentation of the hexafluorobenzene dication formed by photoabsorption in the 30–120 eV energy range

The dissociation pattern of the doubly charged C6F2+6 ion produced by single photon ionization has been investigated in the 27–120 eV energy range using time‐of‐flight (TOF) mass spectrometry, double photoion–photoion coincidence (PIPICO), and triple photoelectron–photoion–photoion coincidence (PEPIPICO) spectroscopies. A ‘‘metastable’’ C6F2+6 ion is observed with an appearance energy of 27.3±0.4 eV dissociating slowly to the lowest thermodynamical limit leading to the ion pair products CF++C5F+5 (appearance energy of 30.7±0.5 eV). At higher energies, several other charge separation reactions appear as well as covalent channels in which neutral fragments are ejected from C6F2+6. Additional pairs of correlated ions are formed by secondary fragmentations. In the threshold region, double ionization of the molecule is probably followed by structural rearrangements to distinct C6F2+6 isomers, each dissociating to specific dissociation channels. Partial cross sections of selected ion pairs measured in the 30–12...