Unimolecular β-hydroxyperoxy radical decomposition with OH recycling in the photochemical oxidation of isoprene

Abstract

A novel process in the photochemical oxidation of isoprene that recycles hydroxyl (OH) radicals hasbeenidentified using first-principles computational chemistry. Isoprene is the dominant biogenic volatile organic compound (VOC), and its oxidation controls chemistry in the forest boundary layer and is also thought to contribute to cloud formation in marine environments. The mechanism described here involves rapid unimolecular decomposition of the two major peroxy radicals (β-hydroxyperoxy radicals) produced by OH-initiated isoprene oxidation. Peroxy radicals are well-known as key intermediates in VOC oxidation, but up to now were only thought to be destroyed in bimolecular reactions. The proc..