Vibrationally resolved 2a2u−1 photoionization of C6F6

We report vibrationally resolved results on 2a2u−1 photoionization of C6F6. Vibrational branching ratios are determined for the ring breathing mode by measuring dispersed fluorescence spectra of the C6F6+ (B̃ 2A2u→X̃ 2E1g) transition. Data are presented in the excitation energy range from 20 to 35 eV, and the vibrational branching ratios show a striking departure from Franck–Condon behavior from 20 to 25 eV. This deviation is attributed to a shape resonance.