Temperature dependences for the reactions of O{sub 2}{sup −} and O{sup −} with N and O atoms in a selected-ion flow tube instrument
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117-5776 (United States)
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)
Rate constants for the reactions of O{sub 2}{sup −} and O{sup −} with N and O atoms have been measured for the first time as a function of temperature from 173 to 500 K for O{sup −} reactions and 173 to 400 K for O{sub 2}{sup −} reactions. Room temperature rate constants for O{sub 2}{sup −} reacting with N and O are 3.1 × 10{sup −10} and 1.7 × 10{sup −10} cm{sup 3} s{sup −1}, respectively, and the corresponding O{sup −} rate constants are 1.7 × 10{sup −10} and 1.5 × 10{sup −10} cm{sup 3} s{sup −1}, in good agreement with previous values. Temperature dependences are about T{sup −1.7} for both O{sub 2}{sup −} reactions and T{sup −0.6} and T{sup −1.3} for the reactions of O{sup −} with N and O, respectively. Branching for the O{sub 2}{sup −} reaction with N is found to predominantly form O{sup −} (>85%) in contrast to previous measurements, which reported NO{sub 2}+e{sup −} as the main channel. Calculations point to the present results being correct. The potential energy surface for this reaction was calculated using density functional theory, coupled cluster with singles, doubles (triples), complete active space self-consistent field, and complete active space second-order perturbation methods and is found to be quite complex, with agreement between the calculated surface and the observed kinetic data only possible through the inclusion of dynamical correlation.
- OSTI ID:
- 22220401
- Journal Information:
- Journal of Chemical Physics, Vol. 139, Issue 14; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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