Regensburg 2010 – scientific programme
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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 59.102: Poster
Wednesday, March 24, 2010, 17:45–20:30, Poster B1
Manipulation of the wetting layer of H2O on Pt(111) — •Sebastian Standop1, Alex Redinger1, Markus Morgenstern2, Thomas Michely1, and Carsten Busse1 — 1II. Physikalisches Insitut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln — 2II. Physikalisches Institut (IIB), RWTH Aachen, D-52056 Aachen
Previous LEED experiments unveiled strong effects of electron exposure on the structure of the adsorbed water layer on Pt(111) [1]. A transition from the √39 × √39 R16.1∘ structure to the simple commensurate √3 × √3 R30∘ arrangement was observed. Upon electron beam induced restructuring also exposure of bare Pt was found.
Using scanning tunneling microscopy we investigated the influence of electron dose, energy and scanning parameters on the √39 × √39 R16.1∘ overlayer. Our results show that above a threshold electron energy of about 4 eV the high order commensurate phase transforms into the √3 × √3 R30∘ overlayer through partial dissociation of water molecules. This superstructure has a higher molecular density than the initial domains with a √39 arrangement which explains the occurrence of uncovered substrate areas after electron beam manipulation. We could rule out that the tip electrical field is of relevance for the structural transition.
[1] J. Harnett, S. Haq and A. Hodgson, Surface Science 528 (2003) 15