In situ X-ray scattering studies of the (111) electrode surface were carried out in NaF, NaCl, LiCl, CsCl, KCl, and NaBr solutions by using grazing-incidence diffraction and reflectivity techniques. The top layer of Au atoms underwent a reversible phase transition between the (1 x 1) bulk termination and a (p x 3) uniaxial discommensurate (striped) phase upon changing the electrode potential. Below the critical potential, p was equal to 23 in all of the solutions. This was identical to that obtained in a vacuum. No ordered array of discommensuration kinks was observed. Above the critical potential, p was between 23 and 30. At sufficiently positive potentials, the surface formed an ideally terminated (111) surface. In negative potential sweeps, the reconstruction began to re-form at the critical potential. An analysis of the potential dependence of the scattered X-ray intensity for various anions in NaF, NaCl, and NaBr solutions supported a unifying model that depended upon the induced surface charge density. The transition to the (1 x 1) phase was much faster than the formation of the reconstructed phase. Cycling the potential in the reconstructed region improved the reconstructed surface order. Adsorption of anions and so-called surface water at the interface was investigated by using specular X-ray reflectivity.

J.Wang, B.M.Ocko, A.J.Davenport, H.S.Isaacs: Physical Review B, 1992, 46[16], 10321-38