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A: Atomphysik
A 7: Clusters II: Non-Metal Clusters, Fullerenes, Nanotubes (joint session A and MO)
A 7.1: Talk
Tuesday, April 3, 2001, 15:45–16:00, H1012
High Resolution Core-Level Spectroscopy of Molecular Van der Waals Clusters — •Roman Flesch1, Werner Tappe1, Andrey A. Pavlychev2, and Eckart Rühl1 — 1Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany — 2St. Petersburg State University, 198904 St. Petersburg, Russian Federation.
Size-dependent properties of molecular Van der Waals clusters are efficiently probed by inner-shell spectroscopy, which is known to be site- and element specific. Recent results on clusters of nitrogen (N2)n and carbon monoxide (CO)n are reported. The experiments are carried out by using the soft X-ray monochromator U49-1-SGM at the high brilliance storage ring facility BESSY-II with a typical energy resolution of E/ΔE>104. Vibrationally resolved spectra of inner-shell excited resonant states, such as C 1s−1π*, N 1s−1π* and O 1s−1 π*, are reported for clusters and molecules. Small spectral shifts are observed in clusters relative to the isolated molecules. These are of the order of a few meV. Changes in Franck-Condon factors are found. Moreover, the line widths and shapes of core-to-valence transitions are different in clusters compared to the free molecules. The results are discussed in terms of size-dependent changes in electronic and geometric structure as well as dynamic stabilization of core-excited molecules that are localized in clusters.