In situ second harmonic generation was applied to investigate the axial symmetries of an Au(111)-electrode inserted in various electrolytes. Evidence was given for two distinct one-fold axial symmetries present in different potential ranges. The first could be associated with the well known Au(111) − (√3 x 23) reconstruction, the second axial symmetry was of unknown origin, but adsorption induced. Whereas the first type was lifted upon adsorption (of oxide, hydroxide, sulphate or bromide ions), the second type was formed in adsorbate dependent potential ranges. The analysis of the anisotropy data also yielded a general linear dependence of the isotropic amplitude (real part) on the charge density.

In situ SHG Studies of Adsorption Induced Surface Reconstruction of Au(111)-Electrodes. B.Pettinger, J.Lipkowski, S.Mirwald: Electrochimica Acta, 1995, 40[1], 133-42