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 59.100: Poster

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

Electron beam induced effects in ice on Pt(111) — •Daniel Schwarz, Herbert Wormeester, and Bene Poelsema — Solid State Physics, IMPACT, University of Twente, The Netherlands

The interactions at the water-solid interface determine a wide range of physical and chemical properties, relevant in nature and technology. The growth of a thin water layer on Pt(111) is considered a model system for studying this interaction. A series of complex crystalline structures were found as a function of the thickness of a thin ice film on this metal surface when grown at temperatures above 135K [1]. Below this temperature strongly amorphous ice growth is found. The thin ice layers (1-50ML) form a delicate structure. A fast restructuring of the film under the influence of an electron beam was found [2]. These energetic electron induced changes prohibit a detailed structural analysis with LEED. Although some lateral lattice structure determination is reported, an IV analysis is beyond the capabilities of a standard LEED system.

Electron induced phenomena can be reduced by using MCP-LEED which allows to use much lower electron current densities compared to conventional LEED. This does not only allow to measure in detail the development of the lattice parameter parallel to the interface with ice thickness, but also opens the possibility for a more detailed analysis via IV-LEED. A quadrupole is used to identify kinetics and composition of the desorbed species after prolonged electron bombardment.

[1] A. Glebov et al., J. Chem. Phys. 106 (1997) 9382

[2] J. Harnett et al., Surface Science. 528 (2003) 15