INSITU SCANNING-TUNNELING-MICROSCOPY OBSERVATIONS OF THE POTENTIAL-DEPENDENT (1X2) RECONSTRUCTION ON AU(110) IN ACIDIC ELECTROLYTES

We report in situ STM results on the structure of the (1 x 2)-reconstructed Au(110) surface in various acidic electrolytes and on the (1 x 1) <--> (1 x 2) structural transformation. A (1 x 2) missing-row reconstructed phase is found at potentials negative of +0.05 V(SCE), while above +0.25 V the unreconstructed (1 x 1) phase prevails. The phase transition in the intermediate potential range is completely reversible, with both phases coexisting in dynamic equilibrium in varying amounts depending on the potential. The reconstruction proceeds via local nucleation and growth of individual missing- and added-row reconstruction elements leading to a large number of characteristic defects, mainly adatom islands. The similarity in mechanism and potential regime of the structural transformation in three different electrolytes makes specific anion effects unlikely.