Time-Resolved Charge Transfer in “Push-Pull” Stilbenes

Intramolecular Charge Transfer (ICT) processes of 4-dimethylamino-4'-nitrostilbene (DNS) in solution are studied by pump-probe absorption spectroscopy with a 100 fs time resolution. The results are compared to transient CARS experiments. Pump-probe results confirm the formation of a radiative ICT state in low polar solvents. In a highly polar solvent (acetonitrile), the formation of a short-lived non-radiative ICT state is observed for the first time. CARS experiments support structural changes associated to ICT processes in highly polar solvents.