Berlin 2008 – scientific programme
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O: Fachverband Oberflächenphysik
O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)
O 55.5: Poster
Wednesday, February 27, 2008, 18:30–19:30, Poster F
Photoelectron Spectroscopy at FLASH: Limits and Perspectives — •Martin Marczynski-Bühlow, Matthias Kalläne, Stefan Hellmann, Sabrina Lang, Claas Thede, Tim Riedel, Sönke Harm, Kai Rossnagel, and Lutz Kipp — Institut für Experimentelle und Angewandte Physik, Universität Kiel, D-24098
The Free Electron Laser in Hamburg (FLASH) produces very brilliant, ultrashort, and coherent photon pulses in the VUV regime.
Employing high-intensity monochromatic VUV–pulses (hν = 115.5 eV, FEL 3rd harmonic) delivered by the PG2 beamline of FLASH we performed angle resolved as well as core–level photoelectron spectroscopy (PES) on the transition metal dichalcogenide 1T–TaS2 in the Mott insulating phase (T = 140 K). For high photon intensities strong space charge (SCE) effects have been observed. To determine the limit where PES is still feasible, the measurements are compared with simulations of SCEs based on the Barnes & Hut Treecode Algorithm originally developed for simulating planetary movements. Furthermore, the perspectives of PES with FEL light in terms of time-resolved pump-probe experiments, spatially and angularly resolved PES with photon sieves [1], and the influence of high photon intensities on the momentum resolved electronic structure as well as on the photoemission process itself will be illustrated.
This work is supported by the Innovationsfond des Landes Schleswig-Holstein.
[1] L. Kipp, M. Skibowski, R. L. Johnson, R. Berndt, R. Adelung, S. Harm and R. Seemann, Nature 414, 184 (2001).