title: Oxidation of bromide ions by hydroxyl radicals: spectral characterization of the intermediate BrOH•-.
abstract: The reaction of (•)OH with Br(-) has been reinvestigated by picosecond pulse radiolysis combined with streak camera absorption detection and the obtained spectro-kinetics data have been globally analyzed using Bayesian data analysis. For the first time, the absorption spectrum of the intermediate species BrOH(•-) has been determined. This species absorbs in the same spectral domain as Br(2)(•-): the band maximum is roughly at the same wavelength (λ(max) = 352 nm instead of 354 nm) but the extinction coefficient is smaller (ε(max) = 7800 ± 400 dm(3) mol(-1) cm(-1) compared with 9600 ± 300 dm(3) mol(-1) cm(-1)) and the band is broader (88 nm versus 76 nm). Quantum chemical calculations have also been performed and corroborate the experimental results. In contrast to Br(2)(•-), the existence of several water-BrOH(•-) configurations leading to different transition energies may account for the broadening of the absorption spectrum in addition to the higher number of degrees of freedom.
authors.affiliation: Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Faculté des Sciences d'Orsay, Bât. 349, 91405 Orsay Cedex, France. isabelle.lampre@u-psud.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lampre
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Marignier
authors.forename: Malaknaz
authors.initials: M
authors.lastname: Mirdamadi-Esfahani
authors.forename: Pascal
authors.initials: P
authors.lastname: Pernot
authors.forename: Pierre
authors.initials: P
authors.lastname: Archirel
authors.forename: Mehran
authors.initials: M
authors.lastname: Mostafavi
mesh_terms: D001965:Bromides / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D010084:Oxidation-Reduction; D011789:Quantum Theory
chemical_list: D001965:Bromides; D007477:Ions; D017665:Hydroxyl Radical