title: Red-Light-Induced Decomposition of an Organic Peroxy Radical: A New Source of the HO2 Radical.
abstract: The gas-phase decomposition of the α-hydroxy methylperoxy radical has been theoretically examined, and the results provide insight into a new source of the hydroperoxy radical (HO2 ) in the troposphere. Bimolecular peroxy decomposition is promoted by the red-light or near-IR radiation excitation. The calculations suggest for the first time, an important chemical role for the H2 O⋅HO2 radical complex that exist in significant abundance in the troposphere. In particular, the reaction of organic peroxy radicals with the HO2 radical and the H2 O⋅HO2 radical complex represent an autocatalytic source of atmospheric HO2 . This reaction is a new example of red-light-initiated atmospheric chemistry that may help in understanding the discrepancy between the observed and measured levels of the HOx at sunrise.
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588 (USA).
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588 (USA). jfrancisco3@unl.edu.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Francisco
keywords: atmospheric chemistry; computational chemistry; potential-energy profiles; radical-molecule reactions; radicals