Intramolecular reorganization energy in zinc phthalocyanine and its fluorinated derivatives: a joint experimental and theoretical study.

We report a high-resolution gas-phase UPS spectrum of zinc phthalocyanine (ZnPc) together with a detailed analysis of the vibronic structure of the first ionization band, showing that ZnPc presents the lowest value of the intramolecular reorganization energy experimentally reported for a molecular organic semiconductor.