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A study of the dissociative recombination of CaO + with electrons: Implications for Ca chemistry in the upper atmosphere
Author(s) -
Bones D. L.,
Gerding M.,
Höffner J.,
Martín Juan Carlos Gómez,
Plane J. M. C.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl071755
Subject(s) - dissociative recombination , afterglow , ion , electron , diffusion , atomic physics , atmosphere (unit) , dissociation (chemistry) , solvated electron , plasma , chemistry , analytical chemistry (journal) , radical , recombination , radiolysis , physics , thermodynamics , astrophysics , nuclear physics , biochemistry , gamma ray burst , organic chemistry , chromatography , gene
The dissociative recombination of CaO + ions with electrons has been studied in a flowing afterglow reactor. CaO + was generated by the pulsed laser ablation of a Ca target, followed by entrainment in an Ar + ion/electron plasma. A kinetic model describing the gas‐phase chemistry and diffusion to the reactor walls was fitted to the experimental data, yielding a rate coefficient of (3.0 ± 1.0) × 10 −7 cm 3 molecule −1 s −1 at 295 K. This result has two atmospheric implications. First, the surprising observation that the Ca + /Fe + ratio is ~8 times larger than Ca/Fe between 90 and 100 km in the atmosphere can now be explained quantitatively by the known ion‐molecule chemistry of these two metals. Second, the rate of neutralization of Ca + ions in a descending sporadic E layer is fast enough to explain the often explosive growth of sporadic neutral Ca layers.