Second harmonic generation for in situ analysis of electrode surface structure

The nonlinear optical technique of second harmonic generation has been used as an in situ probe of surface structure and symmetry at the electrode-electrolyte interface. Rotational anisotropy in the second harmonic (SH) signalprovides valuable information on the degree of structural order at the metal surface. For Ag(111), the observed patterns in the p-and s-polarized SH output agree with current theories and demonstrate that an ordered surface is present. These patterns change as the electrode is electrochemically roughened.