Spectroscopy of Polycyclic Aromatic Hydrocarbon Cations and Complexes Martin Vala, Department of Chemistry, University of Florida, Gainesville, Fl. 32611 The involvement of polycyclic aromatic hydrocarbons (PAHs) and carbon chain clusters in the astrochemistry of the interstellar medium (ISM) has been recognized for over twenty years. While the presence of various metals in the ISM is also well known, the reaction of certain metals with PAHs or carbon clusters has only recently been proposed to account for the observed depletion of these metals in the ISM. In the past year we have shown via matrix isolation infrared spectroscopy and density functional theory calculations that iron, in either the neutral or ionized (Fe+) forms, reacts with PAHs (naphthalene, fluorene, pyrene, and coronene) to form stable complexes. These complexes, particularly the ionic ones, could account for the depletion of iron in the ISM. Mono and bis forms naph We have also found that copper reacts with carbon to form the stable, near-linear copper carbide, Cu C3. If substituted with the isotopes 12C and 13C, CuC3 has been shown to undergo isotopic scrambling or fractionation after irradiation with visible or ultraviolet radiation. The scrambling occurs via a bicyclic Cu C3 intermediate.