Electron Collisional Excitation Rates for O
 <scp>i</scp>
 Using the
 B
 ‐Spline
 
 R
 
 ‐Matrix Approach

Zatsarinny, Oleg; Tayal, S. S.

doi:10.1086/377354

Cited by 45 publications

(25 citation statements)

References 45 publications

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“…The rates are about a factor of five and two greater than ours, respectively. Zatsarinny & Tayal (2003) have published effective collision strengths based on calculations using the B-spline R-matrix approach with non-orthogonal orbitals. They provide data for transitions between the 3 P, 1 D, and 1 S states of the ground configuration and from these states to 23 other excited states.…”

Section: Resultsmentioning

confidence: 99%

“…Perhaps the best estimate of the error is obtained from the scatter among different R-matrix calculations where available. From the comparison with the rates of Zatsarinny & Tayal (2003) and the rates of Berrington & Burke (1981), we would estimate that the rate coefficients have errors of the order of 70% at the temperatures of interest. It is difficult to predict the impact that these new data will have on the results of non-LTE calculations in stellar atmospheres.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

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: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Electron-impact excitation of neutral oxygen

Barklem¹

2006

A&A

105

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“…We took the relative abundance of C + and O to be the solarsystem C/O ratio, 0.46 (Lodders & Palme 2009). We used the collision strengths computed by Bell et al (1998) and Zatsarinny & Tayal (2003) for e−O, and by Tayal (2008) The observed line ratios give an electron density of n e ∼10 4 cm −3 and T = 130 K for the extended emission component (see Figure 4), appropriate for PDRs with incident FUV field strength of G 0 ∼ 100 (Kaufman et al 1999). The values for n e , T and G 0 that we obtain lie in the ranges commonly observed for PDRs on the surface of molecular clouds (Hollenbach & Tielens 1997, indicating that the extended component surrounding the jet is consistent with the emission from a photodissociation region (PDR) on the surface of the OMC-2 cloud.…”

Section: Extended Pdr Emission In Omc-2mentioning

confidence: 99%

Herschel/PACS far-IR spectral imaging of a jet from an intermediate mass protostar in the OMC-2 region

González-García

Manoj

Watson

et al. 2016

A&A

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We present the first detection of a jet in the far-IR [O I] lines from an intermediate mass protostar. We have carried out a Herschel/PACS spectral mapping study in the [O I] lines of OMC-2 FIR 3 and FIR 4, two of the most luminous protostars in Orion outside of the Orion Nebula. The spatial morphology of the fine structure line emission reveals the presence of an extended photodissociation region (PDR) and a narrow, but intense jet connecting the two protostars. The jet seen in [O I] emission is spatially aligned with the Spitzer/IRAC 4.5 µm jet and the CO (6-5) molecular outflow centered on FIR 3. The mass loss rate derived from the total [O I] 63 µm line luminosity of the jet is 7.7 ×10 −6 M yr −1 , more than an order of magnitude higher than that measured for typical low mass class 0 protostars. The implied accretion luminosity is significantly higher than the observed bolometric luminosity of FIR 4, indicating that the [O I] jet is unlikely to be associated with FIR 4. We argue that the peak line emission seen toward FIR 4 originates in the terminal shock produced by the jet driven by FIR 3. The higher mass-loss rate that we find for FIR 3 is consistent with the idea that intermediate mass protostars drive more powerful jets than their low-mass counterparts. Our results also call into question the nature of FIR 4.

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“…As indicated in Table 14, we adopt the values given by Zatsarinny & Tayal (2003) for the transitions they include and those of Bhatia et al (1982) for the additional transitions that they list. Otherwise, we use the Seaton and van Regemorter formulae for radiative and nonradiative transitions, respectively.…”

Section: O I Collisional Excitationmentioning

confidence: 99%

Models of the Solar Chromosphere and Transition Region from SUMER and HRTS Observations: Formation of the Extreme‐Ultraviolet Spectrum of Hydrogen, Carbon, and Oxygen

Avrett

Loeser

2008

ASTROPHYS J SUPPL S

358

234

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We present the results of optically thick non-LTE radiative transfer calculations of lines and continua of H, C iYiv, and O iYvi and other elements using a new one-dimensional, time-independent model corresponding to the average quiet-Sun chromosphere and transition region. The model is based principally on the Curdt et al. SUMER atlas of the extreme ultraviolet spectrum. Our model of the chromosphere is a semiempirical one, with the temperature distribution adjusted to obtain optimum agreement between calculated and observed continuum intensities, line intensities, and line profiles. Our model of the transition region is determined theoretically from a balance between (a) radiative losses and (b) the downward energy flow from the corona due to thermal conduction and particle diffusion, and using boundary conditions at the base of the transition region established at the top of the chromosphere from the semiempirical model. The quiet-Sun model presented here should be considered as a replacement of the earlier model C of Vernazza et al., since our new model is based on an energy-balance transition region, a better underlying photospheric model, a more extensive set of chromospheric observations, and improved calculations. The photospheric structure of the model given here is the same as in Table 3 of Fontenla, Avrett, Thuiller, & Harder. We show comparisons between calculated and observed continua, and between the calculated and observed profiles of all significant lines of H, C iYiv, and O iYvi in the wavelength range 67Y173 nm. While some of the calculated lines are not in emission as observed, we find reasonable general agreement, given the uncertainties in atomic rates and cross sections, and we document the sources of the rates and cross sections used in the calculation. We anticipate that future improvements in the atomic data will give improved agreement with the observations.

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Electron Collisional Excitation Rates for O i Using the B ‐Spline R ‐Matrix Approach

Cited by 45 publications

References 45 publications

Electron-impact excitation of neutral oxygen

Electron-impact excitation of neutral oxygen

Herschel/PACS far-IR spectral imaging of a jet from an intermediate mass protostar in the OMC-2 region

Models of the Solar Chromosphere and Transition Region from SUMER and HRTS Observations: Formation of the Extreme‐Ultraviolet Spectrum of Hydrogen, Carbon, and Oxygen

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