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MO: Fachverband Molekülphysik

MO 23: Atomic Clusters III (with A)

MO 23.6: Vortrag

Donnerstag, 11. März 2010, 15:45–16:00, F 303

Direct observation of fullerene plasmon oscillations in momentum space — •Sanja Korica¹, Burkhard Langer², Axel Reinköster¹, Markus Braune¹, and Uwe Becker¹ — ¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin-Dahlem, Germany — ²Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin-Dahlem, Germany

An extended spherical object which gives rise to standing wave oscillations is C₆₀ [1]. We performed new near threshold measurements for C₆₀ in order to reveal the corresponding threshold behavior. The result was a surprise. The extension of the high energetic sinusoidal behavior to lower energies uncovers a phase jump of π/2 in the plasmon excitation region [2]. By subtraction of the extended regular oscillation from the experimental data we could unfold the oscillatory behavior of the plasmon excitations directly in momentum space for the first time. In addition, after subtraction of the plasmon oscillation the shell thickness dependent beating behavior of the partial cross sections was exhibited much more clearly than demonstrated before. This shows, that Cohen and Fano’s formula [3] provides a very good measure for determining the large scale coherent photoionization behavior as prerequisite for the derivation of energetically more restricted kinds of behavior such as the plasmon oscillations exhibited directly in momentum space for the first time here.
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