The atmospheric impact of the reaction of N2O with NO3: A theoretical study

• Published in: Chemical physics letters Vol. 731; no. C; p. 136605
• Main Authors: Nguyen, Thanh Lam, Romanias, Manolis N., Ravishankara, A.R., Zaras, Aristotelis M., Dagaut, Philippe, Stanton, John F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier B.V 16.09.2019; Elsevier
• Subjects: Chemical Sciences; Chemistry; Engineering Sciences; Environmental Sciences; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ocean, Atmosphere; or physical chemistry; Physics; Reactive fluid environment; Sciences of the Universe; Theoretical and; N2O; NO3; Quantum chemical calculations; kinetics; Atmosphere chemistry
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2019.136605

[Display omitted] •Nitrous oxide is a greenhouse gas and a potential O3-depleting substance.•OH, Cl, and NO3 do not react fast enough with N2O.•These reactions are too slow to be observed experimentally.•A reaction of NO3 with N2O might influence the atmospheric lifetime of N2O.•Mechanism and kinetics of the NO3 + N2O reaction have been studied for the first time. The reaction of N2O with NO3 is studied for the first time using high-level quantum chemical calculations, followed by statistical rate coefficient estimations. Two reaction pathways giving NO2 + N2 + O2 and NO2 + 2NO have been explored. The formation of NO2 + N2 + O2 is exothermic by 30 kcal mol−1 while that of NO2 + 2NO is endothermic by 13 kcal mol−1. Both mechanisms have significant reaction barriers, and the reaction rate constants are very low: about 6 × 10–43 cm3 s−1 at 298 K. Therefore, this reaction is not expected to affect the lifetime of N2O in the atmosphere.