Charge exchange of metastable 2D oxygen ions with N2 in the thermosphere

Abstract

Ababaet-Measurements of N,+ and supporting data made on the Atmosphere Explorer-C satellite in the ionosphere are used to study the charge exchange process The equality k = (5 f 1.7) 5 1O-*o cm3 s-l. This value Iies close to the tower kit of experimental uncertainty of the rate coefficient determined in the laboratory. We have also investigated atomic oxygen quenching of 0+(2D) and iind that the rate coefficient is 2 x 10-l' cm3 s-l to within approximately a factor of two.

AE Reaction Rate Data.

“…From AE-C observations of N 2 + , Torr and Orsini (1977) derived a value of (5 ±2 .5)x10 10 cm 3 s~~ for k 15. The value -10 3 -1 is larger than the rate coefficient of l. Orsini et al .…”

State-Selected and State-to-State Ion−Molecule Reaction Dynamics

“…A major part of our recent efforts has been devoted to ion chemistry studies relevant to planetary atmospheres. ,− Ions appearing in planetary atmospheres are mostly formed by electron impact and solar ultraviolet and VUV dissociation and ionization processes. , Through chemical interactions, ions initially formed by these processes influence the concentrations and temperatures of electrons, ions, and neutral molecules in the atmospheres. Quantitative in situ and laboratory measurements of rate constants and cross sections for reactions involving relevant ionic species are of importance for realistic modeling of reaction cycles in planetary atmospheres. − …”

“…The O + ions formed with a branching ratio − 0.43:0.29:0.28 for O + ( 4 S):O + ( 2 D):O + ( 2 P) by solar VUV photoionization of O atoms are the most abundant ions in the F-region of the Earth's atmosphere. , Because the excited O + ( 2 D) and O + ( 2 P) ions, which lie 3.324 and 5.017 eV above the O + ( 4 S) ground state, are metastable with radiative lifetimes of 3.6 h and 4.57 s, respectively, knowledge about the decay and reaction pathways for O + ( 2 D) and O + ( 2 P) are essential for our understanding of the ion chemistry in the ionosphere. − , It is known that the rates for radiative recombination of O + with electrons are several orders of magnitude smaller than those for dissociative recombination of N 2 + , O 2 + and NO + with electrons. , Thus, the major decay pathways for O + ( 4 S, 2 D, 2 P) and electrons first involve the reactions between O + ( 4 S, 2 D, 2 P) and atmospheric gases. Product O 2 + ions formed in the charge-transfer reaction of O + + O 2 are known to undergo rapid dissociative recombination reactions with electrons, giving rise to excited oxygen atoms .…”

“…Quantitative in situ and laboratory measurements of rate constants and cross sections for reactions involving relevant ionic species are of importance for realistic modeling of reaction cycles in planetary atmospheres. [34][35][36] The O + ions formed with a branching ratio 37-40 0.43:0.29: 0.28 for O + ( 4 S):O + ( 2 D):O + ( 2 P) by solar VUV photoionization of O atoms are the most abundant ions in the F-region of the Earth's atmosphere. 37,41 Because the excited O + ( 2 D) and O + -( 2 P) ions, which lie 3.324 and 5.017 eV above the O + ( 4 S) ground state, are metastable with radiative lifetimes of 3.6 h and 4.57 s, respectively, knowledge about the decay and reaction pathways for O + ( 2 D) and O + ( 2 P) are essential for our understanding of the ion chemistry in the ionosphere.…”

“…37,41 Because the excited O + ( 2 D) and O + -( 2 P) ions, which lie 3.324 and 5.017 eV above the O + ( 4 S) ground state, are metastable with radiative lifetimes of 3.6 h and 4.57 s, respectively, knowledge about the decay and reaction pathways for O + ( 2 D) and O + ( 2 P) are essential for our understanding of the ion chemistry in the ionosphere. [34][35][36]41 It is known that the rates for radiative recombination of O + with electrons are several orders of magnitude smaller than those for dissociative recombination of N 2 + , O 2 + and NO + with electrons. 42,43 Thus, the major decay pathways for O + ( 4 S, 2 D, 2 P) and electrons first involve the reactions between O + ( 4 S, 2 D, 2 P) and atmospheric gases.…”