Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 34: Elektronische Struktur IV
O 34.7: Vortrag
Donnerstag, 27. März 2003, 16:30–16:45, M\"UL/ELCH
Resonance in the (1π)−1 photoemission cross-section of CO on Pt(111) measured by high-harmonic radiation — •Grigorios Tsilimis, Sebastian Wegner, Jörg Kutzner, and Helmut Zacharias — Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, D-48149 Münster
Femtosecond pulses of a table–top, high–repetition rate (1 kHz) Ti:sapphire laser system are focussed into rare gases to produce high-harmonic radiation in the range of hν = 20 to 120 eV (60 − 11 nm). The c(4× 2)-2CO-covered Pt(111) surface is investigated by angle resolved photoelectron spectroscopy (ARUPS) using this radiation. Both the coarse tunability in steps of 3.1 eV as well as a fine tuning within a single harmonic are utilized in the measurements. The photoemission cross section of CO induced structures, in particular the CO 1π orbital, is investigated. For this state a resonance is observed, which has not been reported so far. A resonant excitation of electrons from the occupied 3σ level into the unoccupied 2π* level followed by the autoionization of the 1π CO state or Auger decay is proposed to cause this resonance.