Structures and reactions at Metal/Electrolyte interfaces at the atomic level

Until recently, there had been only few in situ methods available for the s tructural determination of an electrode surface in solution at the atomic l evel. Now several recent investigations have demonstrated scanning tunnelin g microscopy (STM) to be a powerful new technique for in situ characterizat ion, with atomic resolution, of surfaces under potential control. The objec t of this article is to highlight some of the recent progress made, mainly in the authors' laboratory, on in situ STM with atomic resolution. Several selected topics are focused on, including instrumental and experimental asp ects of in situ STM, observation of clean platinum electrode in solution, s pecifically adsorbed anions (halides, cyanide, sulfate) on metal surfaces, and adsorption of organic molecules (benzene and other small molecules) on clean and iodine-modified electrodes.