Berlin 2005 – scientific programme
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MO: Molekülphysik
MO 23: Femtosecond Spectroscopy
MO 23.6: Talk
Saturday, March 5, 2005, 15:15–15:30, HU 2091
Position Sensitive Detection of Fragmentation of Fullerenes after Femtosecond Laser Irradiation — •C.P. Schulz1, M. Boyle1, T. Laarmann1, K. Hansen2, E.E.B. Campbell2, and I.V. Hertel1 — 1Max-Born-Institut, Max-Born-Str. 2a, D-12489 Berlin, Germany — 2Dept. of Experimental Physics, Göteborg University and Chalmers University of Technology, SE-41296 Göteborg, Sweden
The fragmentation of fullerenes after photo excitation is interesting because of the competition between the strong binding energy (10 eV for a C2 loss) and the relatively low ionization energy of 7.6 eV. The photo-fragmentation of fullerenes after nanosecond pulses has been found to proceed through statistical mechanisms and is characterized by sequential C2 loss. Here, we study the fragmentation of fullerenes after femtosecond laser irradiation with a time-of-flight spectrometer and a position sensitive detector (RoentDek). Using statistical models, we are able to extract an initial internal temperature, as well as derive a general formula to predict the velocity distribution of the fragment ions as a function of the number of C2 units lost. The good agreement of the measured velocity distributions indicates that the fragmentation of fullerenes after femtosecond laser irradiation is statistical in nature.