This Small Grant for Exploratory Research is made by the Inorganic, Bioinorganic, and Organometallic Program to support the development of a new method for determining the symmetry and geometry of gas phase transition metal carbonyl anions. Dr. Steven W. Buckner of the Chemistry Department, University of Arizona, will construct a CO laser that will cover wavelengths in the range 1600 to 2000 inverse centimeters. This will enable detailed examination of the C-O stretching bands of various complexes. The experiment will be a new application of wavelength dependent infrared multiphoton dissociation (IRMPD) spectroscopy. In addition to providing a new structural probe of these species, should the early phases of this work be successful, light-driven bimolecular reactions of some organometallic ions would be investigated. Detailed mechanisms of complex gas phase photochemical reactions could thus be determined. %%% Full understanding of gas phase organometallic chemistry requires investigation of both structural changes and energetics during the course of reactions. Here a novel experimental approach to obtaining such important information is proposed. Because difficulties with sensitivity of the method and rearrangement of the reactants could limit its utility, the research is supported by a small exploratory award. If successful, however, the method would be helpful in understanding photochemical and catalytic processes.