Reaction Probability and Infrared Detection of the Primary Ozonide in Collisions of O3 with Surface-Bound C60

The kinetics and mechanism of reactions between gas-phase ozone and surface-bound C-60 have been investigated by monitoring changes to reflection-absorption infrared spectra within a well-characterized film of C-60 during exposure to a controlled flux of pure ozone. These ultrahigh vacuum studies provide direct infrared spectroscopic evidence for the formation and decomposition of a primary ozonide of C-60. The spectral assignments of this highly unstable intermediate have been verified using electronic structure calculations. Theory and experiment revealed that C-60 oxidized nearly exclusively via addition of ozone across the double bond that links two six-carbon-containing rings of the molecule. Following spectral characterization, the initial probability for ozone to react with the surface was found to be 5.8 +/- 0.2 x 10(-4). Once formed, the ozonide quickly thermally decomposed to a variety of carbonyl-containing products.