title: A study of the reaction of N+ with O2: experimental quantification of NO+(a 3Sigma+) production (298-500 K) and computational study of the overall reaction pathways.
abstract: The product branching ratios for NO+(X 1Sigma+) and NO+(a 3Sigma+) produced from the reaction of N+ with O2 have been measured at 298 and 500 K in a selected ion flow tube. Approximately 0.5% of the total products are in NO+(a) at both temperatures, despite the fact that the reaction to form NO+(a) is 0.3 eV exothermic. High-level ab initio calculations of the potential energy surfaces for the N+ + O2 reaction show that the reaction from N+(3P) + O2(3Sigma(g)) reactants starts with an efficient early stage charge transfer to the N(2D) + O2+(X 2Pi) channel, which gives rise to the O2+(X 2Pi) product and, at the same time, serves as the starting point for all of the reaction channels leading to NO+ and O+ products. Pathways to produce NO+(a 3Sigma+) are found to be less favorable than pathways leading to the major product NO+(X 1Sigma+). Production of N(2D) has implications for the concentration of NO in the mesosphere.
authors.affiliation: Air Force Research Laboratory, Space Vehicles Directorate, 29 Randolph Rd., Hanscom Air Force Base, Massachusetts 01731-3010, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Midey
authors.forename: A A
authors.initials: AA
authors.lastname: Viggiano
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Stephan
authors.initials: S
authors.lastname: Irle
authors.forename: Keiji
authors.initials: K
authors.lastname: Morokuma