AVS 53rd International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuM

Paper SS2-TuM4
Lateral Water Ordering at Reconstructed MgO(111) Surfaces

Tuesday, November 14, 2006, 9:00 am, Room 2004

Session: Water-Surface Interactions
Presenter: P.F. Lyman, University of Wisconsin-Milwaukee
Authors: P.F. Lyman, University of Wisconsin-Milwaukee
S.S. Parihar, University of Wisconsin-Milwaukee
H.T. Johnson-Steigelman, University of Wisconsin-Milwaukee
V.L. Shneerson, University of Wisconsin-Milwaukee
R. Fung, University of Wisconsin-Milwaukee
D.K. Saldin, University of Wisconsin-Milwaukee
F.U. Renner, ESRF, Grenoble, France
T.-L. Lee, ESRF, Grenoble, France
J. Zegenhagen, ESRF, Grenoble, France
Correspondent: Click to Email
The polar oxide surface MgO(111) is known to undergo several air-stable reconstructions, including p(2x2) and (@sr@3x@sr@3)R30° phases. The observed structure depends on O partial pressure and temperature. We report on a study of stability and structure of these reconstructions at an aqueous interface. The interface between the bulk water layer (5 µm) and the reconstructed MgO(111) was probed using surface x-ray diffraction. For other substrates, previous measurements of the specular surface truncation rod had revealed that a surface can induce layered ordering in the interfacial water, but measurements of off-specular rods indicated that only weak lateral ordering was present.@footnote 1@ Our study addressed the additional effect of a corrugated, reconstructed interface. Moreover, reflections with smaller in-plane momentum transfers are available when using a reconstructed surface, allowing more sensitive studies of any lateral ordering. For the (@sr@3x@sr@3)R30° phase, the reconstruction was stable in contact with water for many hours. Changes (between wet and dry interfaces) in the non-specular rods closest to the origin (in reciprocal space) reveal changes in the ordered lateral electron density, presumably due to lateral ordering in the water layer. The p(2x2) surface roughened and de-reconstructed almost immediately upon immersion in water. @FootnoteText@ @footnote 1@M.F. Reedijk et al., Phys. Rev. Lett. 90, 066103 (2003) .