The gas-phase reactions of ozone with alkenes can be significant sources of free radicals (OH, HO(2) and RO(2)) in the Earth's atmosphere. In this study the total radical production and degradation products from ethene ozonolysis have been measured, under conditions relevant to the troposphere, during a series of detailed simulation chamber experiments. Experiments were carried out in the Europ...

Cavity ringdown spectra of butyl peroxy radicals have been obtained for their A-X electronic transition in the near-IR. The radicals were produced by two independent chemical methods, allowing unambiguous assignment of the spectra of the four butyl peroxy isomers with probable conformer assignments also possible for a number of cases. Using the analyzed spectra semiquantatively, isomer specific...

The oxygen scavenging of C-centered radicals in microheterogeneous media was studied by investigation of the photolysis of several ketones (dibenzyl ketone (DBK), oand p-methyldibenzyl ketone (o-MeDBK andp-MeDBK) and d,l-2,4-diphenyipentan-3-one (d,~-DPP)) in oxygen-saturated sodium dodecylsulfate (SDS) micellar solution. The acyland benzyl-type radicals initially formed during the photolysis o...

The gas-phase reactions of ozone with alkenes can be significant sources of free radicals (OH, HO2 and RO2) in the Earth’s atmosphere. In this study the total radical production and degradation products from ethene ozonolysis have been measured, under conditions relevant to the troposphere, during a series of detailed simulation chamber experiments. Experiments were carried out in the European ...

p. 2: Revised isoprene oxidation mechanism for low to moderate NOx conditions as proposed earlier (Peeters et al., PCCP, 2009), with 303 K rate coefficients from first principles; Figs. S1 and S2 p. 3: Temperature-dependent rate coefficient expressions for the unimolecular reactions of isoprene hydroxyperoxy radicals, T = 280 to 320 K, as used in this work; Table S1 p. 4: Effects of allyl-stabi...

[1] Extensive chemical characterization of ozone (O3) depletion events in the Arctic boundary layer during the TOPSE aircraft mission in March–May 2000 enables analysis of the coupled chemical evolution of bromine (BrOx), chlorine (ClOx), hydrogen oxide (HOx) and nitrogen oxide (NOx) radicals during these events. We project the TOPSE observations onto an O3 chemical coordinate to construct a ch...

The heterogeneous oxidation of organic aerosol by hydroxyl radicals (OH) can proceed through two general pathways: functionalization, in which oxygen functional groups are added to the carbon skeleton, and fragmentation, in which carbon-carbon bonds are broken, producing higher volatility, lower molecular weight products. An ongoing challenge is to develop a quantitative molecular description o...