Surface crystallography of three catalytically important structures in the Au{111}-Pd system

摘要: Automated Tensor LEED has been used to determine the detailed crystallography of structures formed during Pd deposition on Au{111}. At 200 K, 0.2 monolayer results in a complete lifting clean surface Au{111} reconstruction, with excess Au atoms being squeezed into disordered adlayer added adatoms. coverage at this temperature structure is formed, which orders heating 300 K (1 × 1) predominantly top layer. Further produces overlayer. On annealing ⩾ 500 converts an ordered alloy (3×3)R30° periodicity. This consists least 2 layers Pd2Au alloy. It unique showing constant splitting all Bragg beams, attributed facetting domains oriented only 0.75° from planar surface. rumpled possesses are larger than 100 A width. The discussed relation known catalytic activity for various cyclisation ethyne benzene.