Frankfurt 2006 – wissenschaftliches Programm
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MO: Molekülphysik
MO 13: Molecular Clusters I
MO 13.1: Vortrag
Montag, 13. März 2006, 14:00–14:15, H10
Innershell excitation of free nano particles — •B. Langer1,2, H Bresch1, R Lewinski1, P Brenner1, R. Flesch1, C. Graf1, T. Martchenko3, O. Ghafur3, M. J. J. Vrakking3, and E. Rühl1 — 1Institut für Physikalische Chemie I, Universität Würzburg, Am Hubland, 97074 Würzburg — 2Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin — 3FOM Institute AMOLF, Amsterdam, The Netherlands
We have studied inner shell excitations in free nano particles using synchrotron radiation. Our particles were transferred into the gas phase by an aerosol generator. An additional differential mobilisation analyser (DMA) made it possible to generate a continuous beam of size selected nano particles that was focussed into the vacuum chamber by an aerodynamical lens. This approach allowed us to prepare free nano particles which were produced by colloidal chemistry. We have measured the total electron yield to characterise the electronic structure of nano particles in the region of their inner shell excitations.
First experiments were performed on size selected NaCl nano particles (radius = 50 -175 nm) in the region of the Cl 2p and the Na 1s excitation. Measurements in the region around the O 1s absorption threshold show that these particles contain only little water. In contrast, nanoscopic salt particles (Na2SO4 · 10 H2O) that contain chemically combined water show a significant absorption in this region which might be of interest to study the binding structure of such water. In addition, we have studied the influence of coatings to the electronic structure of free core-shell particles. Here we used ZnS particles (radius = 60 nm) with a 5 nm SiO2 shell.