Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 46: Adsorption VI
O 46.1: Vortrag
Freitag, 31. März 2006, 11:15–11:30, TRE Phys
The Structure of O-p(4x4)/Ag(111): results from surface sensitive x-ray techniques — •A. Stierle1, A. Reicho1, I. Costina1, S. Thiess2, J. Zegenhagen2, and H. Dosch1 — 1MPI für Metallforschung, Heisenbergstraße 3, D-70569 Stuttgart — 2ESRF, B.P. 220, F-38043 Grenoble
Silver plays an important role as an oxidation catalyst and therefore
many fundamental studies have been devoted to Ag surfaces.
One important finding is that after oxidation of Ag(111) at 500 K either
at O2 pressures in the mbar regime, or using NO2 at lower pressures
a p(4x4) superstructure is formed, which was belived to be a prototype
for a surface oxide O-Ag-O trilayer.
The proposed models for this structure [1] are incompatible with the
surface x-ray diffraction data obtained at the MPI-MF beamline at ANKA and
the normal incidence x-ray standing wave results from ID32, ESRF.
Instead, a model is favoured, that includes Ag adatoms on hcp and fcc
sites and oxygen atoms filling the rows in between, which is also supported
by recent scanning tunneling microscopy and core level spectroscopy
results, combined with density functional theory calculations∗.
∗M. Schmid, et al., contribution at this conference
A. Michaelides, K. Reuter, and M. Scheffler. J. Vac. Sci. Technol. A 23, 1487-1497 (2005).