N<sub>2</sub> triplet band systems and atomic oxygen in the dayglow

Broadfoot, A. L.; Hatfield, D. B.; Anderson, E.; Stone, Tom; Sandel, B. R.; Gardner, James A.; Murad, Edmond; Knecht, David J.; Pike, C. P.; Viereck, R. A.

doi:10.1029/97ja00771

Cited by 36 publications

(45 citation statements)

References 33 publications

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“…Hence that enhancement may not be real. For dayglow the measured values [Broadfoot et al, 1997] of the relative populations for levels 0, 1, and 2 agree with the present model. Broadfoot et al also give theoretical predictions for levels 3 -6 which are lower than the current predictions for levels 4-6.…”

Section: Resultssupporting

confidence: 77%

“…[13] Relative distributions deduced in fitting synthetic spectra to observations of dayglow at 200 km [Broadfoot et al, 1997], auroral column emission [Degen, 1982], and aurora at 110 km [Eastes and Sharp, 1987] are also included in Figure 1 by scaling to the appropriate N 2 [A 3 S u + , (n 0 = 0)] value. There is good agreement in the shapes of the distributions for aurora, except that the current model does not predict the enhancement for n 0 = 6 and n 0 = 7 found by Degen.…”

Section: Resultsmentioning

confidence: 99%

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Role of excited N₂ in the production of nitric oxide

2007

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[1] Excited N 2 plays a role in a number of atmospheric processes, including auroral and dayglow emissions, chemical reactions, recombination of free electrons, and the production of nitric oxide. Electron impact excitation of N 2 is followed by radiative decay through a series of excited states, contributing to auroral and dayglow emissions. These processes are intertwined with various chemical reactions and collisional quenching involving the excited and ground state vibrational levels. Statistical equilibrium and time step atmospheric models are used to predict N 2 excited state densities and emissions (as a test against previous models and measurements) and to investigate the role of excited nitrogen in the production of nitric oxide. These calculations predict that inclusion of the reaction N 2 [A 3 S u + ] + O, to generate NO, produces an increase by a factor of up to three in the calculated NO density at some altitudes.

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Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Role of excited N₂ in the production of nitric oxide

2007

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“…Even if accomplished, characterizing the differences in instrumental sensitivities to develop a reliable intensity calibration across such a wide breadth of wavelength is difficult and subject to uncertainty. Nevertheless, two such measurements are discussed below [Broadfoot et al, 1997;Torr et al, 1993]. As we will show, the Herzberg I distribution of photons from these emissions can be fully characterized, allowing one to relate the 297.2 and 557.7 nm line intensities in a meaningful way.…”

Section: Herzberg I Bridgementioning

confidence: 99%

“…This is by far the lowest ratio measured and is in good accord with the value reported here. The fact that two equivalent determinations [Torr et al, 1993;Broadfoot et al, 1997] give values of R differing by a factor of three points to intensity calibration being the most likely cause.…”

Section: Uv/visible Space Shuttle Measurementsmentioning

confidence: 99%

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O(¹S → ¹D,³P) branching ratio as measured in the terrestrial nightglow

et al. 2006

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[1] The branching ratio of the two optically forbidden atmospheric emission lines, O( 1 S À 1 D) at 557.7 nm and O( 1 S À 3 P) at 297.2 nm, is a fixed number in the upper atmosphere because the O( 1 S) level is common to both lines. The value for the ratio A(557.7)/A(297.2) currently recommended by NIST is 16.7, and the ratio found in the laboratory is somewhat larger. Field observations require space-based instruments, in which case calibration between the two wavelength regions is the critical issue. We circumvent this problem by using the O 2 (A-X) Herzberg I emission system as a bridge between the UV region below 310 nm and the ground-accessible region above that wavelength. These two spectral regions can be separately calibrated in terms of intensity, and the results of a disparate set of observations (satellite, rocket, ground-based sky spectra) lead to a quite consistent value of 9.8 ± 1.0 for A(557.7)/A(297.2). This conclusion has consequences for auroral and dayglow processes and for spectral calibration. It is particularly important to ascertain the cause of the substantial difference between this value and those from theory.

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