The Source of Green Light Emission Determined from a Heavy-Ion Storage Ring Experiment

Kella, D.; Vejby-Christensen, L.; Johnson, Philip R.; Pedersen, H. B.; Andersen, Lars H.

doi:10.1126/science.276.5318.1530

Cited by 124 publications

(84 citation statements)

References 20 publications

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“…The x-axes are the projected distances between the two O product atoms, which is roughly proportional to the square root of the KER. 20 The four dissociation limits can easily be distinguished ͑peaks i-iv͒. The spectrum for P1 differs markedly from the spectrum for P5, indicating a vibrational dependence of the dissociation reaction.…”

Section: Partial Rate Coefficients At 0 Evmentioning

confidence: 96%

“…The shape of the distance distributions and the analytical model for their superposition is described in detail in the literature. 20,55 The background contribution was again measured separately for each of the ion-source settings. For these measurements the electrons were turned off and the obtained data again subtracted.…”

Section: Dissociative Recombination Dynamics: Partial Rate Coefficienmentioning

confidence: 99%

“…At the ASTRID ion storage ring, a beam of an unknown vibrational composition of the mixed isotope 16 O 18 O ϩ was used in the studies. 20 In a more recent experiment at the CRYRING ion storage ring, an O 2 ϩ beam was used that consisted of vϭ0 ions only. 21 The corresponding O( 1 S) quantum yields are in good agreement with the theoretical estimates.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of the O( 1 S) quantum yield, experimental values have been found ranging from almost 0.7% to 10%. 9,[17][18][19][20][21] Again, many of these experiments had different, and often unknown, vibrational populations of the parent ions. Some consensus has been reached for the branching fractions of the vibrational ground state of O 2 ϩ (X 2 ⌸ g ) near 0 eV collision energy.…”

Section: Introductionmentioning

confidence: 99%

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Vibrationally resolved rate coefficients and branching fractions in the dissociative recombination of O2+

Petrignani

Zande

Cosby

et al. 2004

The Journal of Chemical Physics

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We have studied the dissociative recombination of the first three vibrational levels of O 2 ϩ in its electronic ground X 2 ⌸ g state. Absolute rate coefficients, cross sections, quantum yields and branching fractions have been determined in a merged-beam experiment in the heavy-ion storage ring, CRYRING, employing fragment imaging for the reaction dynamics. We present the absolute total rate coefficients as function of collision energies up to 0.4 eV for five different vibrational populations of the ion beam, as well as the partial ͑vibrationally resolved͒ rate coefficients and the branching fractions near 0 eV collision energy for the vibrational levels vϭ0, 1, and 2. The vibrational populations used were produced in a modified electron impact ion source, which has been calibrated using Cs-O 2 ϩ dissociative charge transfer reactions. The measurements indicate that at low collision energies, the total rate coefficient is weakly dependent on the vibrational excitation. The calculated thermal rate coefficient at 300 K decreases upon vibrational excitation. The partial rate coefficients as well as the partial branching fractions are found to be strongly dependent on the vibrational level. The partial rate coefficient is the fastest for vϭ0 and goes down by a factor of two or more for vϭ1 and 2. The O( 1 S) quantum yield, linked to the green airglow, increases strongly upon increasing vibrational level. The effects of the dissociative recombination reactions and super elastic collisions on the vibrational populations are discussed.

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Section: Partial Rate Coefficients At 0 Evmentioning

confidence: 96%

Section: Dissociative Recombination Dynamics: Partial Rate Coefficienmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Vibrationally resolved rate coefficients and branching fractions in the dissociative recombination of O2+

Petrignani

Zande

Cosby

et al. 2004

The Journal of Chemical Physics

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“…The branching ratios given in parentheses are from Kella et al [1997]. A comprehensive review on the measurements of the branching ratios for each channel of this reaction is provided by Fox and Hać [1997].…”

Section: Introductionmentioning

confidence: 99%

Pickup ion measurements by MAVEN: A diagnostic of photochemical oxygen escape from Mars

Rahmati

Cravens

Nagy

et al. 2014

Geophysical Research Letters

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A key process populating the oxygen exosphere at Mars is the dissociative recombination of ionospheric O 2 + , which produces fast oxygen atoms, some of which have speeds exceeding the escape speed and thus contribute to atmospheric loss. Theoretical studies of this escape process have been carried out and predictions made of the loss rate; however, directly measuring the escaping neutral oxygen is difficult but essential. This paper describes how energetic pickup ion measurements to be made near Mars by the SEP (Solar Energetic Particle) instrument on board the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft can be used to constrain models of photochemical oxygen escape. In certain solar wind conditions, neutral oxygen atoms in the distant Martian exosphere that are ionized and picked up by the solar wind can reach energies high enough to be detected near Mars by SEP.

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Aurora borealis: Stochastic cellular automata simulations of the excited‐state dynamics of oxygen atoms

Seybold

Kier

Cheng

1999

Int J of Quantum Chemistry

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Emissions from the 1S and 1D excited states of atomic oxygen play a prominent role in creating the dramatic light displays (aurora borealis) seen in the skies over polar regions of the Northern Hemisphere. A probabilistic asynchronous cellular automaton model described previously [Seybold, Kier, and Cheng, J Phys Chem 1998, 102, 886–891] has been applied to the excited‐state dynamics of atomic oxygen. The model simulates the time‐dependent variations in ground (3P) and excited‐state populations that occur under user‐defined probabilistic transition rules for both pulse and steady‐state conditions. Although each trial simulation is itself an independent “experiment,” deterministic values for the excited‐state emission lifetimes and quantum yields emerge as limiting cases for large numbers of cells or large numbers of trials. Stochastic variations in the lifetimes and emission yields can be estimated from repeated trials. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 75: 751–756, 1999

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The Source of Green Light Emission Determined from a Heavy-Ion Storage Ring Experiment

Cited by 124 publications

References 20 publications

Vibrationally resolved rate coefficients and branching fractions in the dissociative recombination of O2+

Vibrationally resolved rate coefficients and branching fractions in the dissociative recombination of O2+

Pickup ion measurements by MAVEN: A diagnostic of photochemical oxygen escape from Mars

Aurora borealis: Stochastic cellular automata simulations of the excited‐state dynamics of oxygen atoms

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