Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)

O 59.5: Poster

Mittwoch, 24. März 2010, 17:45–20:30, Poster B1

THECLA - Setup of a THErmal CLuster Apparatus — •Sabrina Hennes, Stefanie Duffe, and Heinz Hövel — TU Dortmund, Experimentelle Physik I, Otto-Hahn-Str. 4, 44221 Dortmund, Germany

THECLA is a THErmal CLuster Apparatus which produces clusters by supersonic nozzle expansion [1,2]. It enables optical spectroscopy of clusters in a free jet and of the same clusters deposited on substrates or in a matrix material. A hot-cathode plasma ionisation [3] and a moveable Faraday cup for ion-current measurement are installed for an in-situ determination of the cluster mass. Using the cluster velocity of the supersonic expansion, the ion-displacement by an electric field perpendicular to the cluster beam can be used to determine the cluster mass. In addition time-of-flight measurements can be used to analyse the cluster velocity and mass [1]. In first experiments we studied the plasmon resonance of Ag clusters deposited on SiO₂ in vacuum and exposed to air. Using the same samples it is planned to perform XANES measurements of the L-absorption edge at the synchrotron radiation source DELTA to gain detailed information about the structure, the chemical environment and changes of the unoccupied density of states of those clusters [4,5].

[1] O. F. Hagena, Z. Phys. D 20, 425 (1991). [2] H. Hövel et al., Phys. Rev. B 48, 18178 (1993). [3] I. M. Goldby et al., Rev. Sci. Instrum. 68, 3327 (1997). [4] O. Sipr et al., J. Synchrotron Rad. 6, 770 (1999). [5] A. Bzowski et al., Phys. Rev. B 49, 13776 (1994).