Equilibria, kinetics, and optical and infrared photochemistry of ions in the gas-phase will be explored. The studies will be accomplished primarily with ion cyclotron resonance (ICR) spectroscopy combined with conventional and laser light sources. An underlying theme of this study will be to develop an understanding of the intrinsic chemistry of highly reactive ions in relationship to their structure when they are removed from the stabilizing forces of solvent or crystals. Reactions that will be studied in the gas-phase are the SN2 reaction, acyl transfer reactions, reactions at unsaturated carbon, proton transfer processes, electron transfer reactions, energy transfer processes, and reactions of complex ions. %%% This grant from the Organic Dynamics Program supports the continuing research of Professor John I. Brauman at Stanford University. Most of the current knowledge of reactions involving ions (charged species ) is in solution where the solvent greatly influences the reactions and properties of ions. Professor Brauman will continue his studies of the reactions of ions in the gas-phase, where the stabilizing effect of the solvent is no longer present. Under the conditions afforded by the gas-phase, the intrinsic chemistry of highly reactive ions will be studied in relationship to their structure.