Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 8: Electron and spin dynamics

O 8.7: Vortrag

Montag, 26. März 2012, 12:00–12:15, A 060

Orbital Symmetry Dependent Electron Transfer through Molecules Assembled on Metal Substrates — •Florian Blobner¹, Pedro Coto², Francesco Allegretti¹, Michel Bockstedte², Oscar Rubio-Pons², Haobin Wang³, David Allara⁴, Michael Zharnikov⁵, Michael Thoss², and Peter Feulner¹ — ¹Physik-Department E20, Technische Universität München, 85748 Garching, Germany — ²Institut für Theoretische Physik und Interdisziplinäres Zentrum für Molekulare Materialien, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany — ³Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University, Las Cruces, 88003 New Mexico, USA — ⁴Departments of Chemistry and Material Science, Pennsylvania State University, 16802 Pennsylvania, USA — ⁵Angewandte Physikalische Chemie, Universität Heidelberg, 69120 Heidelberg, Germany

Femtosecond charge transfer dynamics in self-assembled monolayers of cyano-terminated ethane-thiolate on gold substrates was investigated with the core hole clock method. Electrons from the nitrogen K-shell are state-selectively excited into the two symmetry-split π^* orbitals of the cyano end group with x-ray photons of well-defined polarization. The charge transfer times from these temporarily occupied orbitals to the metal substrate differ significantly. Theoretical calculations show that these two π^* orbitals extend differently onto the alkane backbone and the anchoring sulfur atom, thus causing the observed dependence of the electron transfer dynamics on the symmetry of the orbital.