Structure analysis of oxygen-adsorbed tungsten (0 0 1) surface

Structure of the tungsten (0 0 1) surface annealed at 1200 K for the saturation coverage of oxygen, W(0 0 1)-2×1–O, has been studied by low-energy electron diffraction (LEED) and the symmetrized automated tensor LEED program. The optimized structure is that with missing rows of tungsten atoms and double rows of oxygen atoms. The layer separation between the oxygen atom and the topmost tungsten atom layer is 0.50±0.06 Å, the distance between oxygen rows is 2.4±0.3 Å and all other separations between tungsten atoms are the same as bulk values. The distance between the oxygen atom and the tungsten atom agrees well with sum of atomic radii of oxygen and tungsten. Oxygen atoms are located in the threefold hollow site at the tungsten (0 1 1) facet appearing on the tungsten (0 0 1) surface with missing rows.