title: A kinetic study of the reactions FeO+ + O, Fe+.N2 + O, Fe+.O2 + O and FeO+ + CO: implications for sporadic E layers in the upper atmosphere.
abstract: These gas-phase reactions were studied by pulsed laser ablation of an iron target to produce Fe(+) in a fast flow tube, with detection of the ions by quadrupole mass spectrometry. Fe(+).N(2) and Fe(+).O(2) were produced by injecting N(2) and O(2), respectively, into the flow tube. FeO(+) was produced from Fe(+) by addition of N(2)O, or by ligand-switching from Fe(+).N(2) following the addition of atomic O. The following rate coefficients were measured: k(FeO(+) + O --> Fe(+) + O(2), 186-294 K) = (3.2 +/- 1.5) x 10(-11); k(Fe(+).N(2) + O --> FeO(+)+ N(2), 294 K) = (4.6 +/- 2.5) x 10(-10); k(Fe(+).O(2) + O --> FeO(+) + O(2), 294 K) = (6.3 +/- 2.7) x 10(-11); and k(FeO(+) + CO --> Fe(+) + CO(2), 294 K) = (1.59 +/- 0.34) x 10(-10) cm(3) molecule(-1) s(-1), where the quoted uncertainties are a combination of the 1sigma standard errors in the kinetic data and the systematic experimental errors. The surprisingly slow reaction between FeO(+) and O is examined using ab initio quantum calculations of the relevant potential energy surfaces. The importance of this reaction for controlling the lifetime of sporadic E layers is then demonstrated using a model of the upper mesosphere and lower thermosphere.
authors.affiliation: School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
authors.forename: K R S
authors.initials: KR
authors.lastname: Woodcock
authors.forename: T
authors.initials: T
authors.lastname: Vondrak
authors.forename: S R
authors.initials: SR
authors.lastname: Meech
authors.forename: J M C
authors.initials: JM
authors.lastname: Plane
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D002248:Carbon Monoxide / Q000737:chemistry*; D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry*; D007477:Ions; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D007477:Ions; C000499:ferric oxide; D002248:Carbon Monoxide; D007501:Iron; D009584:Nitrogen; D010100:Oxygen