AVS 51st International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThA

Paper SS1-ThA1
Partial Dissociation of Water on the Surface of ZnO

Thursday, November 18, 2004, 2:00 pm, Room 210B

Session: Metal Oxides and Clusters IV: Oxide Surface Chemistry
Presenter: B. Meyer, Ruhr-Universität Bochum, Germany
Authors: B. Meyer, Ruhr-Universität Bochum, Germany
D. Marx, Ruhr-Universität Bochum, Germany
O. Dulub, Tulane University
U. Diebold, Tulane University
M. Kunat, Ruhr-Universität Bochum, Germany
D. Langenberg, Ruhr-Universität Bochum, Germany
C. Wöll, Ruhr-Universität Bochum, Germany
Correspondent: Click to Email
Due to the interplay between chemical bonding, van der Waals forces, and hydrogen bonding, the interaction of water with solid substrates gives rise to complex phenomena such as complete dissociation, partial dissociation at defects, multilayer formation, and wetting. Recently, an intriguing, yet controversial, intermediate scenario was advanced, where the interaction between water molecules results in a partial dissociation of water on perfect surfaces, leading to superlattices with long-range order. Applying a broad array of methods, including diffraction (He-atom scattering, LEED), scanning tunneling microscopy, and thermodynamic measurements supplemented by density-functional total-energy, Car-Parrinello molecular dynamics, and STM computations, conclusive evidence is given that such a phenomenon is encountered for H@sub 2@O on the perfect ZnO(10-10) surface. At monolayer coverage, every second water molecule is found to auto-dissociate, subject to a low activation barrier, upon a favorable hydrogen-bonding interaction with a neighboring water molecule, i.e. without the need to invoke defects or impurities. This process leads to a (2x1) superlattice with long-range order which is stable from well below room temperature up to temperatures close to the boiling point of liquid water.