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CP: Chemische Physik

CP 8: Spektroskopie

CP 8.5: Vortrag

Montag, 22. März 1999, 17:30–17:45, Gg

Ultrafast Electron Transfer Reactions at Surfaces — •Ramakrishna Sesha Shankar¹, Volkhard May², and Frank Willig¹ — ¹Hahn-Meitner-Institut, Berlin — ²Institut für Physik, Humboldt Universität zu Berlin

The photoinduced electron transfer from a surface-attached dye molecule into empty conduction band states of a semiconductor is studied theoretically. Modelling the continuum of band states in the semiconductor by a large number of potential energy surfaces in the energy range of interest one can account for the irreversible character of the transfer process. The dynamics are

described within an approach based on the time–dependent Schrödinger equation for the electron vibrational system including the ultrafast external laser pulses. Recent femtosecond pump probe experiments on perylene on a TiO₂ surface will be compared and conditions under which one can observe temperature independent electron-transfer, the formation of a hot vibrational molecule or an electronic wavepacket in the semiconductor band state continuum will be addressed.