ABSTRACT

Structure of Adsorbate Monolayers .......................................................................... 726 20.5.6 Macrocyclic Adsorbates ........................................................................................... 729

Few scientic developments in the last 50 years have revolutionized the understanding of the solid/ liquid interface as much as the invention of the scanning tunneling microscope (STM).1 The emergence of electrochemical scanning tunneling microscopy (EC-STM) in the late 1980s and early 1990s,2-5 coupled with the rapid advancement of nanofabrication techniques and the increasing use of ultramicroelectrodes and nanoelectrodes,6-8 has dramatically expanded capabilities to relate observed electrochemistry to the properties of single atoms and molecules at the electrode surface. The ability of EC-STM to act as an atomic scale, in situ probe of electrochemical systems affords it applications in nanoscale electrochemistry that would be inaccessible to techniques such as cyclic voltammetry or surface sensitive spectroscopies, where experimental data are averaged over a large fraction of the working electrode area.