Kinetics of reactions of ground state nitrogen atoms (^4S_(3/2)) with NO and NO_2

Abstract

The discharge flow technique has been used with resonance fluorescence detection of N atoms to study the fast radical-radical reaction of ground state nitrogen atoms (^4S_(3/2)) with NO and NO_2. The rate constants obtained are (in units of cm^3 molecule^(−1) s^(−1)) k_1 = (2.2±0.2) × 10^(−11) exp[(160±50)/T] in the temperature range 213 K ≤ T ≤ 369 K for N + NO → N_2 + O and k_2 = (5.8±0.5) × 10^(−12) exp [(220±50)/T] in the temperature range 223 K ≤ T ≤ 366 K for N + NO_2 → N_2O + O. The reported error limits are at the 95% confidence level. The reaction kinetics are consistent with other radical-radical reactions, essentially no enthalpic barrier is observed. Substitution of the measured rate of R_1 for the value recommended hi the latest Jet Propulsion Laboratory compendium [DeMore et al., 1992] results in a small change in the concentration of ozone predicted in a two-dimensional photochemical model. Modeled ozone concentrations are higher (approximately 1%) in the high-latitude upper stratosphere as a result of a 3–10% reduction in the calculated concentrations of NO_y.

Additional Information

© 1994 American Geophysical Union. Manuscript Accepted: 8 Jul 1994. Manuscript Received: 7 Mar 1994. Paper number 94JD01823. We wish to thank P.S. Stevens and D.W. Toohey for experimental assistance. Discussions with J.P.D. Abbatt and Susan Solomon are gratefully acknowledged. This work was supported by NSF grant ATM-8601126. P. Wennberg acknowledges the support of the NSF Graduate Student Fellowship Program.

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