Berlin 2001 – scientific programme

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MO: Molekülphysik

MO 14: Spektroscopy II

MO 14.8: Talk

Friday, April 6, 2001, 17:30–17:45, H1058

K-edge excitation of variable size sulfur clusters — •Werner Tappe¹, Roman Flesch¹, Dmitri Novikov², Wolfgang Drube², Andrey A. Pavlychev³, Nobuhiro Kosugi⁴, and Eckart Rühl¹ — ¹Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany — ²Hasylab (DESY), Notkestr. 85, 22603 Hamburg, Germany — ³St. Petersburg State University, 198904 St. Petersburg, Russian Federation — ⁴Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan.

Size-dependent properties of free sulfur clusters are investigated by inner-shell excitation. The experiments are carried out at the BW-1 beamline (HASYLAB, DESY, Hamburg) in the excitation regime of the sulfur K-edge (2450-2500 eV). Total ion yields are used to study the inner-shell absorption of variable-size clusters. Time-of-flight mass spectrometry is applied to investigate changes in cluster size as a function of the evaporation of sulfur. The results from K-edge excitation experiments are compared to earlier studies on the L-edge excitation regime (160-240 eV). Ab initio-MR-SDCI-calculations and Extended-Hückel calculations on variable-size clusters are presentend. These are used to investigate size-dependent changes in the electronic as well as the geometric structure of sulfur clusters.