Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)
O 41.47: Poster
Dienstag, 23. März 2010, 18:30–21:00, Poster B1
Cluster-induced desorption of alkali halides from metals and insulators - influence of substrate and adsorbate configuration — B.-J. Lee1, C.R. Gebhardt2, H. Schröder3, K.L. Kompa3, and •M. Dürr1 — 1Fakultät Angewandte Naturwissenschaften, Hochschule Esslingen, Esslingen — 2Bruker Daltonik GmbH, Bremen — 3Max-Planck-Institut für Quantenoptik, Garching
Cluster-induced desorption is a versatile tool for the investigation of surface adsorbates. During cluster surface collision, the system is heated to high temperatures on a very short time scale, thus activating reactions not accessible by means of conventional heating. As an example, fragmentation-free desorption of biomolecules as large as 6000 u from various surfaces has been demonstrated [1].
For surface adsorbates prepared wet-chemically from alkali halide solutions, we show that the surface configuration, especially the influence of water molecules, can be monitored by cluster-induced desorption. As long as the anions are effectively screened by a hydration shell, they are efficiently desorbed by means of cluster impact. To higher surface temperatures, the hydration shell is lost and a strong adsorbate-surface bond prevents desorption of the anions. Cations are seen to desorb from metals via a neutral desorption channel with subsequent charge separation in the cluster whereas only a positive signal is observed for desorption from insulators.
[1] Gebhardt et al., Angew. Chem. Int. Ed. 48, 4162 (2009).