The yield of N(2<i>D</i>) atoms in the dissociative recombination of NO+

Kley, D.; Lawrence, G. M.; Stone, Edward J.

doi:10.1063/1.434491

Cited by 76 publications

(12 citation statements)

References 25 publications

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“…The sequential reactions N(2D ) + CO 2 producing NO followed by NO + N(4S) yielding N a are by far the most important in reducing the total dayside production of excited and ground state N-atoms to the net available for nightside transport. The reaction producing NO § followed by its dissociative recombination serve to redistribute the forms of atomic-N. A standard value of g = 0.75 for branching to N(ZD) is usually chosen (Kley et al, 1977). In addition, partial recovery of N(4S) atoms is obtained by quenching of N(ZD) by O and CO above the N(4S) peak.…”

Section: No Nightglowmentioning

confidence: 99%

Structure, luminosity, and dynamics of the Venus thermosphere

Fox

Bougher

1991

Space Sci Rev

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We review here observations and models related to the chemical and thermal structures, airglow and auroral emissions and dynamics of the Venus thermosphere, and compare empirical models of the neutral densities based in large part on in situ measurements obtained by the Pioneer Venus spacecraft.Observations of the intensities of emissions are important as a diagnostic tool for understanding the chemical and physical processes taking place in the Venus thermosphere. Measurements, ground-based and from rockets, satellites, and spacecraft, and model predictions of atomic, molecular and ionic emissions, are presented and the most important sources are elucidated. Coronas of hot hydrogen and hot oxygen have been observed to surround the terrestrial planets. We discuss the observations of and production mechanisms for the extended exospheres and models for the escape of lighter species from the atmosphere. Over the last decade and a half, models have attempted to explain the unexpectedly cold temperatures in the Venus thermosphere; recently considerable progress has been made, although some controversies remain. We review the history of these models and discuss the heating and cooling mechanisms that are presently considered to be the most important in determining the thermal structure. Finally, we discuss major aspects of the circulation and dynamics of the thermosphere: the sub-solar to anti-solar circulation, superrotation, and turbulent processes.

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Section: No Nightglowmentioning

confidence: 99%

Structure, luminosity, and dynamics of the Venus thermosphere

Fox

Bougher

1991

Space Sci Rev

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“…At lower altitudes near 100 km the simple theory is totally inadequate, and even the more complicated models are not able to explain the observed variations of NO[Cravens et al, 1979].Odd nitrogen is produced from molecular nitrogen either by direct dissociation by photons or photoelectrons, or by a combination of ionization and ion-neutral chemistry. At 200 km, the two important sources are dissociative recombination of NO + which produces N atoms in the 2D metastable state 76% of the time and in the 4S ground state 24% of the time[Kley et al, 1977], and reaction of N2 + with atomic oxygen which produces mostly N(2D). For the simple theory one only needs to know the ratio of the production of Nvery important in the F region, but due to the strong temperature dependence of K4, it becomes much less important at lower altitudes where the neutral temperature is lower.…”

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confidence: 99%

The global distribution of nitric oxide at 200 km

Cravens¹

1981

J. Geophys. Res.

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Measurements of nitric oxide at 200 km by the ultraviolet nitric oxide experiment on Atmosphere Explorer D are used to demonstrate the dependence of NO on latitude, longitude, and magnetic activity. NO is more abundant in the summer hemisphere than in the winter hemisphere and is more abundant during magnetically active times than during quiet times. A simple photochemical theory is used to show that the knowledge of local composition and temperature is sufficient to explain the variations of nitric oxide at this altitude.

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“…6,8 At elevated collision energies, new dissociation channels open up and the present experiments reveal that these limits are also populated. The N( 2 D)-containing channel has a branching fraction close to unity near 0 eV collision energy.…”

Section: Discussionmentioning

confidence: 56%

“…In the Earth's atmosphere, the following properties of the DR process are important. 8 Theoretical calculations have been performed by Schneider et al 9 to try to explain the resonant feature in the cross section at 5 eV collision energy. Second, the branching fractions deserves attention, as the product atoms are fast and reactive species.…”

Section: Introductionmentioning

confidence: 99%

Dissociative recombination of NO+: Dynamics of the X 1Σ+ and a 3Σ+ electronic states

Hellberg

Rosén

Thomas

et al. 2003

The Journal of Chemical Physics

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We have studied the dissociation dynamics of NO ϩ ions in their ground, X 1 ⌺ ϩ , and first excited metastable, a 3 ⌺ ϩ states, induced by the capture of electrons of variable collision energy in the dissociative recombination ͑DR͒ process. The branching over the different dissociation channels has been measured in a merged-beam experiment on the heavy-ion storage ring, CRYRING. In accord with previous observations, NO ϩ (X 1 ⌺ ϩ ,vϭ0) ions dissociate dominantly to the N( 2 D) ϩO( 3 P) product limit at 0 and 1.2 eV collision energies. In contrast to earlier reports, the spin-forbidden N( 4 S)ϩO( 1 D) dissociation limit contributes 0͑Ϯ2͒% at 0 eV. At 5.6 eV a new channel coupled to the production of ground-state atoms becomes more important, but no increase in the production of ground-state product atoms was observed. All observed branching fractions compare very favorably with predictions from a simple statistical model, which is based on the multiplicity of each dissociation limit in combination with spin conservation during the dissociation and the initial electron capture. We also report the distribution of fragment pairs from the DR reaction involving the metastable a 3 ⌺ ϩ state. This state is found to dissociate to nearly all of the energetically allowed product pairs. The lifetime of the a 3 ⌺ ϩ state is found to be 730͑Ϯ50͒ ms, in agreement with earlier, sometimes indirect, observations. The experimental observations have been complemented with ab initio calculations on the different radiative decay processes both for the X 1 ⌺ ϩ and the a 3 ⌺ ϩ states. It is found that vibrational relaxation via infrared radiation is faster for NO ϩ (a 3 ⌺ ϩ ,vϾ0) ions than the electronic decay of these metastable-state ions to the ground state.

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The yield of N(2D) atoms in the dissociative recombination of NO+

Cited by 76 publications

References 25 publications

Structure, luminosity, and dynamics of the Venus thermosphere

Structure, luminosity, and dynamics of the Venus thermosphere

The global distribution of nitric oxide at 200 km

Dissociative recombination of NO+: Dynamics of the X 1Σ+ and a 3Σ+ electronic states

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