Spectroscopic Studies of the Chemistry of Ozone: Applications to Atmospheric Chemistry and Semiconductors Bruce S. Ault Department of Chemistry University of Cincinnati Cincinnati, OH 45221-0172 Abstract The reaction of ozone with alkenes is a principal route to the removal of these volatile organic compounds from the atmosphere. For 50 years, indirect evidence supporting the Criegee mechanism for this reaction has accumulated, yet the principal intermediates have not been observed. Also, O3 is beginning to see application as an oxygen source in the chemical vapor deposition of metal oxide thin films through reaction with appropriate organometallic compounds. However, very little is known about the mechanistic details of the reactions leading to thin film formation. The matrix isolation technique, operating near 12 K, is uniquely suited for the isolation, identification and characterization of a wide range of reactive intermediates. Different methods may be used to deposit matrices, thereby allowing control over the time available for reaction between the precursors, as well as the available energy. Theoretical calculations using ab initio and density functional methods provide a powerful complement to the experimental studies. Using these approaches, the sequence of intermediates in the reactions of O3 with alkenes and organometallic compounds will be discussed.