Frankfurt 2006 – scientific programme
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A: Atomphysik
A 17: Hauptvortr
äge: Cluster in starken Laserfeldern
A 17.3: Invited Talk
Thursday, March 16, 2006, 11:40–12:10, H7
Ultrafast Processes in Photoexcited Metal Cluster studied by Pump-Probe Photoelectron Spectroscopy — •M. Neeb, J. Stanzel, F. Burmeister, and W. Eberhardt — BESSY, Albert-Einstein Str. 15, D-12489 Berlin
Pump-Probe photoelectron spectroscopy with ultrashort laser pulses is a unique tool to receive real-time information on the excited-state dynamics such as nuclear motion and electron relaxation of photoexcited species. In this respect metal clusters have attracted considerable attention as their size-dependent properties address the gap between the discrete nature of atoms and molecules and the continuous band structure associated with condensed materials. For transition metal clusters with an open d-shell, such as Wn, Nin, Pdn, Ptn, it turns out that even very small clusters show ultrafast electron dynamics, thermalisation and photodesorption of ligand molecules which are typically for bulk systems. Time scales of tens to hundreds of femtoseconds have been measured. On the other hand, photoexcited states of noble metal clusters with a large HOMO-LUMO band gap, e.g. Aun, show a typical molecular-like dynamical behaviour, which is mainly attributed to configurational changes of the geometry such as wavepacket motion and isomerisation of the photoexcited species. In this contribution the dynamics of different metal cluster anions will be discussed by means of time-resolved photoelectron spectroscopy with femtosecond laser pulses.