Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 75: Particles and clusters
O 75.6: Vortrag
Donnerstag, 29. März 2012, 17:15–17:30, MA 041
Ag clusters on SiO2 and in matrices: UV-VIS absorption and XANES — •Stefanie Duffe1, Sabrina Hoffmann1, Kamil Latussek1, David Engemann1, Christian Sternemann1, Christoph J. Sahle1, Heinz Hövel1, Ralph Wagner2, and Pieter Glatzel3 — 1TU Dortmund, Experiment. Physik I/DELTA, Dortmund, Germany — 2BU Wuppertal, Fachgruppe Physik-Materialwiss., Wuppertal, Germany — 3ESRF, Grenoble, France
We produce Ag clusters by supersonic nozzle expansion using THECLA, a THErmal CLuster Apparatus [1,2] which was designed to enable optical spectroscopy of clusters in a free jet and deposited on silica glass (SiO2) [2] or in matrices. The optical properties and the UV-VIS absorption band of Ag clusters alter significantly with size, shape, interparticle spacing and the properties of the local environment. We investigate the plasmon resonance of Ag clusters on SiO2, in PDMS (polydimethylsiloxane) or aerogel before and after exposure to air by optical spectroscopy [3]. XANES measurements at the Ag L1,2,3-edges [4] were carried out at the synchrotron radiation sources DELTA and ESRF. Embedding the clusters into PDMS [5] or aerogel enables the investigation of a much higher amount of separated clusters which is otherwise limited by coalescense and electromagnetic coupling.
[1] O. F. Hagena, Z. Phys. D 20, 425 (1991). [2] H. Hövel et al., Phys. Rev. B 48, 18178 (1993). [3] U. Kreibig et al. In: Advances in Metal and Semiconductor Clusters Vol. 4, (ed. M.A. Duncan), JAI press Inc., 345 (1998). [4] P. Behrens et al., Z. anorg. allg. Chem. 625, 111 (1999). [5] L. Ravagnan et al., J. Phys. D 42, 082005 (2009).