T1, T2 state energies and electron affinities of small α,ω-diphenylpolyenes investigated by anion photodetachment photoelectron spectroscopy and excited-state theory.

Photodetachment photoelectron spectroscopy (PD-PES) on molecular radical anions provides electron affinities and direct spectroscopic access to the lowest triplet states T(1) and T(2) of the corresponding neutral molecules. Herein, we apply this method to investigate trans-stilbene (SB), all-trans-1,4-diphenyl-1,3-butadiene (DPB), and all-trans-1,6-diphenyl-1,3,5-hexatriene (DPH). Our gas-phase T(1) energies agree with previous measurements on condensed crystals.

Direct spectroscopy of contact charge transfer states: possible consequences for tryptophan excited-state deactivation pathways by O2 and formation of reactive oxygen species.

This paper demonstrates that photodetachment photoelectron spectroscopy (PD-PES) of non-covalently bound heteromolecular anion clusters allows direct access to neutral contact charge transfer (CCT) states. The 2,2'-bithiophene.indole cluster is investigated as a model system in such a way that both chromophores have similar optical excitation cross-sections and hence the PD-PES shows the signature of both molecules.