INFLUENCE OF STRUCTURAL DEFECTS, STEPS AND KINKS, ON OXYGEN-ADSORPTION ON RHENIUM SINGLE-CRYSTALS

Oxygen adsorption on Re (0001), Re (S) [14 (0001) × (1011)], and Re (S) [6 (0001) × (1676)] has been studied by Auger electron spectroscopy and by low energy electron diffraction. Presence of kinks on this last plane gives a more important amount of oxygen adsorbed than on the two other surfaces. On these three surfaces heating to 500 K is necessary to get ordered structures. The (2 × 2) pattern observed on Re (0001) corresponds to θ = 1/2 and results from the superposition of three domains with unit cell P (2 × 1) at 120° to each other. On the two other surfaces, the presence of steps favorises the development of one particular domain with the shortest side of its unit cell parallel to the step direction. Surface with kinks reconstructs when heated at 800 K after saturation with oxygen at room temperature, while the two other surfaces are stable under the same conditions. This reconstruction could be explained by the formation of a superficial layer of ReO3. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA