title: Kinetic studies of reactions of the nitrate radical (NO3) with peroxy radicals (RO2): an indirect source of OH at night?
abstract: A discharge-flow system, coupled to cavity-enhanced absorption spectroscopy (CEAS) detection systems for NO3 at lambda=662 nm and NO2 at lambda=404 nm, was used to investigate the kinetics of the reactions of NO3 with eight peroxy radicals at P approximately 5 Torr and T approximately 295 K. Values of the rate constants obtained were (k/10(-12) cm3 molecule-1 s-1): CH3O2 (1.1+/-0.5), C2H5O2 (2.3+/-0.7), CH2FO2 (1.4+/-0.9), CH2ClO2 (3.8(+1.4)(-2.6)), c-C5H9O2 (1.2(+1.1)(-0.5)), c-C6H11O2 (1.9+/-0.7), CF3O2 (0.62+/-0.17) and CF3CFO2CF3 (0.24+/-0.13). We explore possible relationships between k and the orbital energies of the reactants. We also provide a brief discussion of the potential impact of the reactions of NO3 with RO2 on the chemistry of the night-time atmosphere.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK.
authors.forename: Stewart
authors.initials: S
authors.lastname: Vaughan
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Canosa-Mas
authors.forename: Christian
authors.initials: C
authors.lastname: Pfrang
authors.forename: Dudley E
authors.initials: DE
authors.lastname: Shallcross
authors.forename: Laura
authors.initials: L
authors.lastname: Watson
authors.forename: Richard P
authors.initials: RP
authors.lastname: Wayne