Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 40: Particles and Clusters I
O 40.1: Vortrag
Mittwoch, 28. März 2007, 15:45–16:00, H38
Surface strain of Au clusters analysed by transmission electron holography — •Radian Popescu1, Erich Müller1, Dagmar Gerthsen1, Matthias Wanner1,2, Marco Schowalter3, Andreas Rosenauer3, Arthur Böttcher4, and Manfred Kappes4 — 1Laboratorium für Elektronenmikroskopie and Center for Functional Nanostructures,Universität Karlsruhe, D-76128 Karlsruhe, Germany — 2Forschungsinstitut für Pigmente und Lacke e.V., D-70569 Stuttgart, Germany — 3Institut für Festkörperphysik, Universität Bremen, D-28359 Bremen, Germany — 4Institut für Physikalische Chemie, Universität Karlsruhe, D-76128 Karlsruhe, Germany
We have carried out an accurate quantitative analysis of the dependence of the mean inner Coulomb potential (MIP) on the particles thickness for Au nano-clusters deposited on amorphous carbon (a-C) substrate taking into account the strain relaxation of the cluster surface atoms. It was shown that the high experimental cluster MIP values of about 80 V measured for the 0.5 nm Au clusters radii can be accounted for only by the strain of the surface atoms. The MIP value of Au volume atoms (atoms which have the Au-bulk coordination number) of V=32.1+-3.6 V we have derived, is in good agreement with previous theoretical estimations of the Au bulk MIP values. The theoretical method developed here to calculate the MIP is not only applicable to the special case of Au clusters, but can be extended to any type of metallic materials.