Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)
O 42.122: Poster
Mittwoch, 25. März 2009, 17:45–20:30, P2
Towards an understanding of the vibrational spectrum of the neutral Au7 cluster — •Luis Mancera and David M. Benoit — Nachwuchsgruppe Theorie - SFB 569, University of Ulm, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
Most experimental vibrational studies on neutral gold nanoclusters have focused on charged particles. For neutral clusters, such studies have been limited in the past to Au2 and Au3. Only very recently, vibrational spectra of a few small neutral gold clusters in gas-phase have been reported, using far-infrared multiple-photon dissociation (FIR-MPD) spectroscopy [1]. Among them, Au7 receives a particular attention since it is in a size regime in which anions and cations are known to adopt planar structures. In this contribution, we address the prediction of the vibrational spectrum of the Au7 cluster from first principles. Since discrepancies between experimental and theoretical spectra are often attributed to anharmonic effects, we also investigate the vibrational spectrum of this cluster, using the vibrational self-consistent field method (VSCF), which includes anharmonic coupling between vibrational modes. Besides anharmonicity, we discuss other issues affecting the prediction of the spectrum, such as polymorphism and the theoretical description of the underlying potential energy surface.
[1] P. Gruene, D. M. Rayner, B. Redlich, A. F. G. van der Meer, J. T. Lyon, G. Meijer, and A. Fielicke, Science 321, 674 (2008)