Ozone is an important reactant in the troposphere because it is reactive with many organic species, especially alkenes. Ozonolysis products often have lower vapor pressures than the initial reactants and therefore are a dominant source of secondary organic aerosol (SOA) in the atmosphere. Key intermediates in ozonolysis are the primary ozonide (POZ) and the Criegee intermediate (CI). However, the POZ and the CI decompose too rapidly to be observed in solution. In 1972, Heiklen et al. studied simple alkene/ozone reactions on a cold surface using offline infrared spectroscopy. (J. Amer. Chem. Soc. 94, 4856-4864). A similar apparatus has been built to perform ozonolysis reactions on a liquid nitrogen cooled window under vacuum. However, in the current study, real-time Fourier Transform Infrared Spectroscopy (FTIR) is used. Preliminary proof-of-concept experiments with ozone and 2,3-dimethyl-2-butene yield FTIR spectra indicating the presence of reactants, intermediate species, and products on the cold window surface. Temperature Programmed Reaction Spectroscopy of intermediates isolated on the cold window surface will constrain key decomposition barrier heights. This in turn will reveal factors controlling reaction product distributions for substituted compounds typically found in the atmosphere.

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