Electron-impact excitation of atomic oxygen:3P-3s5S0and3P-s3S0

Rountree, S.P.

doi:10.1088/0022-3700/10/13/025

Cited by 26 publications

(7 citation statements)

References 22 publications

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“…The ratios with respect to our values are roughly 1.3, 0.4 and 0.8 respectively. For the 3 P→ 5 S o , 3 S o transitions, they calculated collision rates from the cross sections of Rountree (1977). The cross sections of Rountree are significantly larger at the threshold than modern calculations, including our results, resulting in their rates being a factor of about 2.5 greater than ours.…”

Section: Resultscontrasting

confidence: 50%

Electron-impact excitation of neutral oxygen

Barklem¹

2006

A&A

105

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Aims. Our goal was to calculate transition rates from ground and excited states in neutral oxygen atoms due to electron collisions for non-LTE modelling of oxygen in late-type stellar atmospheres, thus enabling the reliable interpretation of oxygen lines in stellar spectra. Methods. A 38-state R-matrix calculation in LS -coupling has been performed. Basis orbitals from the literature are adopted, and a large set of configurations are included to obtain good representations of the target wave functions. Rate coefficients are calculated by averaging over a Maxwellian velocity distribution. Results. Estimates for the cross sections and rate coefficients are presented for transitions between the seven lowest LS states of neutral oxygen. The cross sections for excitation from the ground state compare well with existing experimental and recent theoretical results.

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Section: Resultscontrasting

confidence: 50%

Electron-impact excitation of neutral oxygen

Barklem¹

2006

A&A

105

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“…Unfortunately, the task of accounting for these channels is complicated by the role of many weak transitions that have been known to classical spectroscopists for decades but are often in wavelength regions that are very difficult to observe in situ or in the laboratory, and thus they have been avoided by experimentalists and largely ignored in It is important to note that the 21304 ,t. cross-section values given in Table 1 apply [1974] 3s 5Sø cross-section values are too small or that the photoelectron flux needs to be increased. Of these two options the first is not too promising, since the apparent a(3s 5Sø) value is already quite large compared to theory [Smith, 1976;Rountree, 1977]. Finally, it is interesting to note that the revised cross-section values for the O I(3s' 3Dø-2p 3p; •989 3.)…”

Section: Alpha (11215 A) By Electron Impact On H 2 [Mumma and Zipfmentioning

confidence: 97%

“…The experimental O I cross-section values are quite large, and this in itself has been a matter of considerable concern, since the experimental values and the results of recent quantum scattering calculations differ by a factor of • 2.5 or more [Smith, 1976;Rountree, 1977]. However, since the calculated 3s 3Sø oscillator strength used in the theoretical studies had a probable error of 25-50%, the experimental and theoretical results were just barely compatible when cascade was included.…”

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confidence: 99%

Electron impact excitation of atomic oxygen: Revised cross sections

Zipf¹,

Erdman²

1985

J. Geophys. Res.

100

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Revised cross‐section values for the excitation of the O I(3s ³S°‐2p ³P; λ1304 Å), O I(3d ³D°‐2p ³P; λ1027 Å), and O I(3s′ ³D°‐2p ³P; λ989 Å) resonance transitions by electron impact on atomic oxygen are presented from threshold to 300 eV. These results are smaller than the excitation cross sections used in some airglow models by a factor of ∼2.8. The revised values are in good agreement with recent quantum‐scattering calculations. The downward revision is required by new laboratory studies in which the direct and dissociative cross sections for λ1304 Å excitation were normalized with small probable error to the O and O2 ionization cross sections. The results also reflect new advances in VUV optical calibration techniques. A number of outstanding airglow problems are simplified by these revisions.

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“…Finally, there are significant differences between the collisional data used in the two cases. Haisch et al (1977) used collision rates obtained from distorted wave calculations of Sawada & Ganas (1973); the rates used in the Carlsson & Judge (1993) atomic oxygen model are taken from theoretical close coupling calculations of Rountree (1977) and are smaller. Additionally, the collisional rate in the 3 S– 3 P 2,1,0 transitions is approximately eight times larger than the value used by Haisch et al (1977).…”

Section: Resultsmentioning

confidence: 99%

O I line emission in cool stars: calculations using partial redistribution

Koncewicz¹,

Jordan²

2007

Monthly Notices of the Royal Astronomical Society

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Radiative transfer calculations have been performed for five cool stars: α Tau, β Gem, Procyon, ε Eri and the Sun, for the purpose of investigating the behaviour of the O i emission over a wide range of stellar types, and its dependence on coherent photon scattering. These stars span a range of spectral types from F5 iv–v to K5 iii and surface gravities 1.25 < log g* < 4.75. Particular attention has been paid to the calculation of the flux in the resonance triplet around 1305 Å which is pumped by H Lyβ, including the effects of partial redistribution (PRD) and cross‐redistribution of photons. These are the first calculations for the resonance triplet in giant stars using a full PRD treatment. Calculations of the predominantly collisionally excited intersystem doublet at 1355, 1358 Å are included, and it is found that the ratio of these fluxes shows the effects of opacity. The flux in the forbidden line at 1641 Å is calculated for the giant stars and the effects of coherent scattering on this line are investigated. The discrepancy between the calculated and observed fluxes in the O i lines is used to infer the inadequacy of single‐component chromospheric models.

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Electron-impact excitation of atomic oxygen:³P-3s⁵S⁰and³P-s³S⁰

Cited by 26 publications

References 22 publications

Electron-impact excitation of neutral oxygen

Electron-impact excitation of neutral oxygen

Electron impact excitation of atomic oxygen: Revised cross sections

O I line emission in cool stars: calculations using partial redistribution

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