Gas phase kinetics of the reactions of NaO with H2, D 2, H2O, and D2O

Abstract

The gas phase reactions of the NaO radical with H2, D 2, H2O, and D2O were studied in a flow tube reactor at room temperature. The reaction of NaO with H2 has two exothermic product channels, NaOH + H and Na + H2O. Both channels were observed and the Na formation channel produces some Na in the 3 2P state. The rate constants for the abstraction channel for H 2 and D2 reactants are (2.6 ± 1.0) × 10 -11 and (1.1 × 0.4) × 10-11 cm3 molecule-1 s-1 at 296 ± 2 K. The reaction of NaO with H2O was shown to be second order and the products are assumed to be NaOH and OH. The rate constants for H2O and D2O reactants are (2.2 ± 0.4) × 10-10 and (1.2 ± 0.2) × 10-10 cm3 molecule-1 s-1 at 298 ± 1 K. The measured NaO + H2O rate constant is compared to the predicted collision rate constant from a model based on the large attractive dipole-dipole force between NaO and H2O. The role of these reactions in mesospheric Na chemistry is briefly discussed. © 1987 American Institute of Physics.