The structure of the mixed OH+H2O overlayer on Pt{111}

Held, G., Clay, C., Barrett, S. D., Haq, S. and Hodgson, A. (2005) The structure of the mixed OH+H2O overlayer on Pt{111}. The Journal of Chemical Physics, 123 (6). 064711. ISSN 0021-9606 doi: 10.1063/1.1996572

Abstract/Summary

The structure of the mixed p(3x3)-(3OH+3H(2)O) phase on Pt{111} has been investigated by low-energy electron diffraction-IV structure analysis. The OH+H2O overlayer consists of hexagonal rings of coplanar oxygen atoms interlinked by hydrogen bonds. Lateral shifts of the O atoms away from atop sites result in different O-O separations and hexagons with only large separations (2.81 and 3.02 angstrom) linked by hexagons with alternating separations of 2.49 and 2.81/3.02 A. This unusual pattern is consistent with a hydrogen-bonded network in which water is adsorbed in cyclic rings separated by OH in a p(3x3) structure. The topmost two layers of the Pt atoms relax inwards with respect to the clean surface and both show vertical buckling of up to 0.06 angstrom. In addition, significant shifts away from the lateral bulk positions have been found for the second layer of Pt atoms. (C) 2005 American Institute of Physics.