title: Kinetic study of the reaction Ca+ + N2O from 188 to 1207 K.
abstract: Ion-molecule reactions involving metallic species play a central role in the chemistry of planetary ionospheres and in many combustion processes. The kinetics of the Ca(+) + N(2)O --> CaO(+) + N(2) reaction was studied by the pulsed multiphoton dissociation at 193 nm of organo-calcium vapor in the presence of N(2)O, followed by time-resolved laser-induced fluorescence spectroscopy of Ca(+) at 393.37 nm (4(2)P(3/2) <-- 4(2)S(1/2)). This yielded k(188-1207 K) = 5.45 x 10(-11) (T/300 K)(0.53) exp(282 K/T) cm(3) molecule(-1) s(-1), with an estimated accuracy of +/-13% (188-600 K) and +/-27% (600-1207 K). The temperature dependence of this barrierless reaction, with a minimum in the rate coefficient between 400 and 600 K, appears to be explained by the role of N(2)O vibrational excitation. This is examined using a classical trajectory treatment on a potential energy surface calculated at the B3LYP/6-311+g(2d,p) level of theory.
authors.affiliation: School of Environmental Sciences, University of East Anglia, Norwich, UK. fontia@rpi.edu
authors.forename: John M C
authors.initials: JM
authors.lastname: Plane
authors.forename: Tomas
authors.initials: T
authors.lastname: Vondrak
authors.forename: Sarah
authors.initials: S
authors.lastname: Broadley
authors.forename: Biljana
authors.initials: B
authors.lastname: Cosic
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ermoline
authors.forename: Arthur
authors.initials: A
authors.lastname: Fontijn