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A: Atomphysik
A 4: Clusters I: Metal Clusters (joint session A and MO)
A 4.10: Talk
Monday, April 2, 2001, 18:00–18:15, H1012
Pump-probe fs-photoelectron spectroscopy of small silicon cluster anions — •Markus Maier, Michael Schätzel, Frank Sommer, Nina Morgner, Bernd v.Issendorff, and Hellmut Haberland — Fakultät für Physik, Universität Freiburg, H.Herderstr.3, 79104 Freiburg
The dynamics of excited states of Sin− (n=4 to 11) have been examined by time resolved photoelectron spectroscopy. The clusters have been produced in a laser evaporation source, size selected by a reflectron time-of-flight mass spectrometer and irradiated by fs-laser pulses in the interaction region of a magnetic bottle type electron spectrometer. For the excitation 800 nm pulses (width 100 fs) were used, while the electron detachment was done by either 800 nm pulses or by 400 nm pulses (width 140 fs). Photoelectron spectra have been measured as a function of the laser intensity and of the time delay between the pulses. The results clearly show that relaxation processes occur, which proves that the electron detachment results from a two step excitation via an intermediate state and not just from two-photon absorption. The relaxation times obtained from the first experiments show a strong size dependence, ranging from a few 10 fs up to several 100 fs.