This grant in the Organic Dynamics Program supports the research of Dr. Matthew Platz at Ohio State University. Dr. Platz will continue to investigate the spectroscopy and reaction mechanisms of transient intermediates such as radicals, polyradicals and carbenes. His work will emphasize chemical and physical methods including laser flash photolysis and low temperature matrix isolation spectroscopy. A principal goal will be to measure the kinetics of reactions of alkyl, dialkyl and aromatic carbenes. These studies will test dynamical theories of chemical reactions which have entropic but no enthalpic barriers. He will test for the presence of reversibly formed intermediates in the reaction of carbenes with olefins and nucleophiles. Spin-forbidden reactions of triplet carbenes with singlet reagents will be examined in detail.