NANOSCALE ELECTROCHEMISTRY, the use of electrodes and an electrically conducting liquid solution to drive chemical reactions that are confined to nanometer scales, has been achieved by German researchers (Rolf Schuster, Fritz Haber Institute, Berlin, Schuster_R@FHI-Berlin.mpg.de) employing a special scanning tunneling microscope called an "electrochemical STM." In their setup, the researchers immersed the STM's needlelike probe and the gold surface they wanted to study in an electrolyte consisting of copper sulfate and sulfuric acid. The STM's electrically conducting needle and the metallic gold surface acted like two electrodes in the setup. Then, the researchers applied 60-nanosecond-length voltage pulses between the needle and the gold surface, resulting in surface pits with 5 nm diameter and depths of 0.3-1 nm. The researchers believe that the voltage pulse oxidized the gold surface (caused it to lose electrons), creating gold ions which were then attracted to the tip, where they were reduced (i.e., they gained electrons). Reversing the voltage, they deposited 1-nm-high, 8-nm-diameter clusters of copper (formed by the reduction of copper ions from the electrolyte). The ultrashort pulses allow the researchers to enforce electrochemical changes on a local level. (Schuster et al., Physical Review Letters, 22 June 1998; figures at Physics News Graphics)