K and mixed K+O adlayers on Rh(110).
The evolution of the structure of the adlayers and the substrate during adsorption of K and coadsorption of K and O on Rh(110) is studied by scanning tunneling microscopy and low-energy electron diffraction. The K adsorption at temperature above 450 K leads to consecutive (1x4), (1x3), and (1x2) missing-row reconstructions for coverage up to 0.12 ML, which revert back to (1x3) and (1x4) with increasing coverage up to 0.21 ML. The coadsorption of different oxygen amount at T>450 K and eventually following reduction-reoxidation cycles led to a wealth of coadsorbate structures, all involving substrate missing-row-type reconstructions, some including segmentation of Rh rows along the [110] direction. The presence of K stabilizes the (1x2) missing-row reconstruction, which facilitates the formation of a great variety of very open (10x2)-type reconstructions at high oxygen coverage, not observed in the single adsorbate systems.
Günther
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Department Chemie, Ludwig-Maximilians Universtät München, Butenandtstrasse 11 Haus E, 81377 München, Germany. sebastian.guenther@cup.uni-muenchen.de
Hoyer
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Marbach
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Imbihl
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Esch
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Africh
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Comelli
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Kiskinova
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