Robert Whetten of Georgia Institute of Technology is supported by the Experimental Physical Chemistry Program in his studies of gold nanocrystals passivated by a monolayer of n-alkylthiol(ate) groups. The major objectives of this work are to (a) determine the structure of a passivated nanocrystalline substance; (b) quantify the solubilities and miscibilities of a mixture of molecular nanocrystals; (c) develop a technique for generating beams (and thus mass spectra) of nanocrystals with the passivation layer intact; (d) study the etching and annealing processes; (e) determine the energy-level patterns of small metal particles of previously determined structure; (f) measure the kinetics of annealing, etching, adsorption-passivation in nanocrystalline processing; and (g) create conducting arrays from molecular nanocrystal solids. Finally, these studies will be extended to cesium iodide nanocrystals passivated by alkyl-chain organic acids/salts. These studies will have a tremendous impact in the area of materials research. Nanometer-scale single crystallites can be prepared in such a way that they retain a near-ideal structure yet are stable against dissolution or further growth, even when in contact with each other. This stability is due to the adsorption of `surfactants` that form compact and ordered monolayers on the crystalline surfaces. With techniques developed in Whetten's lab, he is able to make a beam out of these nanoparticles and then mass-select them, necessary steps for full characterization of these materials.
