In 1962, Edwin Hart and John Boag of Argonne National Laboratory saw a novel absorption peak in the spectrum of water that had been blasted with high-energy electrons. They identified that peak as evidence for electrons in solution—solvated electrons. An individual water molecule, though, does not accept an electron. That means the solvation phenomenon is a cooperative one involving a number of molecules. To learn about the forces responsible for bulk solvation, chemists turned to tiny anionic (negatively charged) water clusters with tens of molecules or fewer. Cluster studies also enable scientists to explore how very small systems are fundamentally different from their bulk cousins.
By 1984, anionic clusters of water molecules had been successfully created in the lab. By decade’s end, they had been subjected to theoretical and experimental studies. The result of those explorations was an inconclusive answer to a seemingly straightforward question: Are the electrons in...
