Corral, I; Gonzalez, L; Lauer, A; Freyer, W; Fidder, H; Heyne, K
CHEMICAL PHYSICS LETTERS 2008, 452(1-3), p. 67-71
The electronic excited states of anthracene-9,10-endoperoxide giving rise to singlet oxygen generation (1O2) or homolytic O-O cleavage have been unambiguously characterized using multi-configurational second order perturbation theory MS-CASPT2/CASSCF, with inclusion of solvent interactions, femtosecond polarization resolved UV/IR pump-probe, and steady-state fluorescence experiments. The S1 state, responsible for homolytic O-O cleavage, is observed at 34400 cm-1. Determination of the transition dipole moment direction of the 37000 cm-1 band, confirms the assignment of the S4 state, from which 1O2 is generated, and allows assigning the other electronic states. Furthermore, it is demonstrated that APO can emit after electronic excitation.