Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 12: Symposium: Size-Selected Clusters at Surfaces I
(Invited Speakers: Karl-Heinz Meiwes-Broer, Heinz Hövel, Thorsten Bernhardt)

O 12.2: Hauptvortrag (ohne Erstattung)

Montag, 25. Februar 2008, 14:00–14:30, MA 005

Supported Magic Numbers for Size-Selected Ag Clusters on Fullerene Layers — •H. Hövel¹, S. Duffe¹, L. Patryarcha¹, T. Richter¹, B. Sieben¹, C. Yin², B. von Issendorff², and M. Moseler^3,4 — ¹Technische Universität Dortmund, Experimentelle Physik I — ²Universität Freiburg, Fakultät für Physik — ³Fraunhofer-Institut für Werkstoffmechanik IWM, Freiburg — ⁴Freiburg Materials Research Center

Mass selected clusters from Ag₅₅⁺ to Ag_{561 ± 5}⁺ were deposited on HOPG and Au(111) functionalized with monolayers (ML) of C₆₀ molecules, which proved to be a new and promising choice for the investigation of mass selected clusters. Depositions at 165 K gave extremely narrow cluster height distributions in STM images measured at 77 K. Molecular dynamics simulations for the deposition suggest softlanding with minor distortions of the icosahedral cluster shape at the cluster-fullerene interface [1]. Using C₆₀ /HOPG or 2 ML C₆₀ /Au(111) the cluster heights are stable for more than 12 h at room temperature (RT). For 1 ML C₆₀ /Au(111) the cluster height decreases and finally all clusters disappear at RT. Molecular dynamics simulations reveal a process by which the clusters decay atom by atom through 1 ML C₆₀ /Au(111) at RT. A sharp maximum at 1.7 nm cluster height forms during the cluster decay, indicating that there exists some metastable ’supported magic number’. For the soft-landed clusters we measured identical spectral features for individual clusters with the same selected size using STS at 5 K.

[1] S. Duffe et al., Eur. Phys. J. D (2007), published online