title: Kinetic and mechanistic studies of the recombination of OH with NO2: vibrational deactivation, isotopic scrambling and product isomer branching ratios.
abstract: The kinetics and mechanism of the three-body recombination of OH with NO2 were studied using a pulsed laser photolysis pulsed laser induced fluorescence technique. The rate coefficients for deactivation of vibrationally excited OH (v = 1-5) by NO2 were found to be independent of vibrational level with a value of (6.4 +/- 0.3) x 10(-11) cm3 molecule s (-1) at 298 K. The rate coefficient for reaction of 18OH with NO2 was measured and found to be much faster than for unlabeled OH with a "zero pressure" rate of 1 x 10(-11) cm3 molecule(-1) s(-1) at 298 K and 273 K. Observation of temporal profiles of 16OH and 18OH suggest that isotopic scrambling in the initially formed [H18ON16O2] complex is complete on the microsecond time scale of our experiments. The rate coefficient for reaction of unlabeled OH with NO2 was measured at 413 K in 400 Torr of He. Biexponential temporal profiles were obtained and are consistent with a 10 +/- 3% yield of the weakly bound HOONO isomer.
authors.affiliation: University of Miami, Rosenstiel School of Marine and Atmospheric Science, Division of Marine and Atmospheric Chemistry, 4600 Rickenbacker Causeway, Miami FL 33149, USA.
authors.forename: Luca
authors.initials: L
authors.lastname: D'Ottone
authors.forename: Dieter
authors.initials: D
authors.lastname: Bauer
authors.forename: Pedro
authors.initials: P
authors.lastname: Campuzano-Jost
authors.forename: Melissa
authors.initials: M
authors.lastname: Fardy
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hynes