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MO: Molekülphysik

MO 27: Poster: Femtosecond Spectroscopy

MO 27.8: Poster

Tuesday, March 14, 2006, 16:30–18:30, Labsaal

External Electric Field Effects on Ultrafast Electron Transfer Dynamics — •A.K. Singh, J. Konradi, A.V. Scaria, and A. Materny — International University Bremen, Bremen

The ubiquitous nature of electron transfer (ET) reactions has made them a subject of extensive theoretical and experimental research for many decades. However, the number of studies concerning the effect of a static electric field on intramolecular and intermolecular ET processes is limited. An external electric field is expected to influence the rate of the charge separation process considerably in a photo-excited donor-acceptor system through a significant modification of the free energy change (Δ G). Additionally, changes of the electronic coupling between the initial and final states of the ET process have an important influence. Due to a large dipole moment associated with the radical ion pairs produced in the charge separation process, Δ G changes in the presence of the external field. As the electron transfer rate is a function of Δ G, the reaction dynamics for the production of radical ion pairs is influenced by the introduced perturbation of the system. Depending on the magnitude of the dipole moment and its orientation relative to the electric field, the forward ET rate depends on the applied field. In our contribution, we present results of investigations of the ultrafast ET dynamics under the influence of an external electric field by means of femtosecond time-resolved spectroscopy.