Düsseldorf 2007 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 22: Poster II - Atomic clusters
A 22.5: Poster
Donnerstag, 22. März 2007, 16:30–18:30, Poster B
Structure and Dynamics of Na Clusters Deposited on Insulator Surfaces — •Matthias Bär1, Mathias Winkler2, Lyudmila Moskaleva2, Paul-Gerhard Reinhard1, Eric Suraud3, and Notker Rösch2 — 1Institut für Theoretische Physik II, Universität Erlangen-Nürnberg — 2Institut für Theoretische Chemie, Technische Universität München — 3Laboratoire de Physique Theorique, Universität Paul Sabatier, Toulouse
We study small Na clusters deposited on insulating surfaces like Ar or MgO(001). For this purpose, we employ the time-dependent local-density approximation for the electrons combined with molecular dynamics for the cluster ions (TDLDA-MD). The surface atoms/ions are treated as classical particles interacting with the cluster electrons via local pseudopotentials, while the long range dipole interaction is taken into account through polarization potentials.
In a first exploration, we investigate the influence of the surface on the structure and optical response of small Na clusters. In all cases, we find ground-state configurations which maintain the geometry of the free clusters. Planar isomers which would indicate wetting are energetically disadvantageous.
The optical spectrum is still dominated by the Mie plasmon peaks which are shifted surprisingly little because the two large effects, namely core repulsion the surface atoms/ions (blue shift) and dynamical polarizability of the surface (red shift), almost cancel each other.
In a further step, we discuss the detailed dynamics of cluster deposit on the surface.