With support from the Organic Dynamics Program, Dr. Turecek will investigate the preparations, stabilities, and dissociations of hypervalent oxonium, ammonium, and sulfonium radicals that are generated and analyzed via neutralization- reionization mass spectrometry. In addition, fragmentations of neutral species will be employed for the structural elucidation of complex organic compounds by mass spectrometry. %%% Hypervalent radicals represent a class of unstable species in which the formal valence of an atom exceeds its normal coordination number in the given oxidation state. Dissociations of small hypervalent radicals often display deuterium (H-2) and O-18 isotope effects of unusual magnitude; the nature of these effects is not well understood. Dr. Turecek will study hypervalent radicals in the gas phase by employing the recently developed technique of neutralization reionization mass spectrometry. In the gas phase, hypervalent radicals can undergo exothermic dissociations to afford stable products. Thus, these species hold promise as a novel method by which mass spectroscopy can be used for organic structural analysis.