The kinetics of the reaction of CHOO with ozone has been studied by monitoring CHOO using time-resolved infrared (IR) absorption spectroscopy, which utilized the fast chirped IR pulse train from a quantum cascade laser [J. Chem. Phys., 2017, 146, 244302]. CHOO was prepared by photolyzing a gas mixture of CHI/O/O at 352 nm; the photolysis wavelength was chosen to minimize the photodissociation of O. The measured rate coefficient at 298 K and 30 Torr is (6.7 ± 0.5) × 10 cm s, independent of pressure from 30 to 100 Torr. The result indicates that previous ab initio calculations either underestimated or overestimated this reaction rate by one order of magnitude or more. The result also implies that, the reaction of the Criegee intermediate with ozone may play a role in laboratory studies of ozonolysis of alkenes. However, this reaction would not compete with other CHOO sinks in the atmosphere.

The region 1273-1290 cm