Rate coefficients for electron impact excitation of helium-like ions within the Dirac<i>R</i>-matrix approach

Kimura, E.; Nakazaki, Shinobu; Berrington, K A; Norrington, P. H.

doi:10.1088/0953-4075/33/17/322

Cited by 24 publications

(47 citation statements)

References 29 publications

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“…For S xv and Ca xix, the previous version of CHIANTI used the R-matrix calculations of Kimura et al (2000) that provided collision strengths between the 1s 2 , 1s2l and 1s3l levels. Excitation to the 1s4l and 1s5l were the hydrogenic collision strengths of Sampson et al (1983).…”

Section: New Database Formatmentioning

confidence: 99%

CHIANTI – An atomic database for emission lines. Version 8

Zanna

Dere

Young

et al. 2015

A&A

441

407

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We present version 8 of the CHIANTI database. This version includes a large amount of new data and ions, which represent a significant improvement in the soft X-ray, extreme UV (EUV) and UV spectral regions, which several space missions currently cover. New data for neutrals and low charge states are also added. The data are assessed, but to improve the modelling of low-temperature plasma the effective collision strengths for most of the new datasets are not spline-fitted as previously, but are retained as calculated. This required a change of the format of the CHIANTI electron excitation files. The format of the energy files has also been changed. Excitation rates between all the levels are retained for most of the new datasets, so the data can in principle be used to model highdensity plasma. In addition, the method for computing the differential emission measure used in the CHIANTI software has been changed.

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Section: New Database Formatmentioning

confidence: 99%

CHIANTI – An atomic database for emission lines. Version 8

Zanna

Dere

Young

et al. 2015

A&A

441

407

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“…The collision strengths for the levels up to n = 3 of Zhang & Sampson (1987) have been replaced with those of Kimura et al (2000), calculated with a Dirac-R-Matrix code. Kimura et al (2000) provide effective collision strengths in the temperature range 10 6 -10 7.6 .…”

Section: S XVmentioning

confidence: 99%

“…Kimura et al (2000) provide effective collision strengths in the temperature range 10 6 -10 7.6 . The new data produce differences in the emissivities of the 1s 2 1 S 0 -1s 2p 3 P 1,2 and 1s 2 1 S 0 -1s 2s 3 S 1 transitions of less than 10%.…”

Section: S XVmentioning

confidence: 99%

“…The effective collision strengths for the levels up to n = 3 of Zhang & Sampson (1987) have been replaced with the Dirac-R-Matrix collision strengths of Kimura et al (2000), which are provided in the range 2.5 × 10 6 -10 8 K. The new collision strengths result in differences of up to 20% in the emissivity of the 1s 2 1 S 0 -1s 2s 3 S 1 transition, and differences of about 10% in the forbidden lines and in the 1s 2 -1s 3p transition.…”

Section: Ca XIXmentioning

confidence: 99%

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CHIANTI – an atomic database for emission lines

Dere¹,

Landi²,

Young³

et al. 2009

A&A

464

451

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Aims. The goal of the CHIANTI atomic database is to provide a set of atomic data for the interpretation of astrophysical spectra emitted by collisionally dominated, high temperature, optically thin sources. Methods. A complete set of ground level ionization and recombination rate coefficients has been assembled for all atoms and ions of the elements of H through Zn and inserted into the latest version of the CHIANTI database, CHIANTI 6. Ionization rate coefficients are taken from the recent work of Dere (2007, A&A, 466, 771) and recombination rates from a variety of sources in the literature. These new rate coefficients have allowed the calculation of a new set of ionization equilibria and radiative loss rate coefficients.For some ions, such as Fe viii and Fe ix, there are significant differences from previous calculations. In addition, existing atomic parameters have been revised and new atomic parameters inserted into the database. Results. For each ion in the CHIANTI database, elemental abundances, ionization potentials, atomic energy levels, radiative rates, electron and proton collisional rate coefficients, ionization and recombination rate coefficients, and collisional ionization equilibrium populations are provided. In addition, parameters for the calculation of the continuum due to bremsstrahlung, radiative recombination and two-photon decay are provided. A suite of programs written in the Interactive Data Language (IDL) are available to calculate line and continuum emissivities and other properties. All data and programs are freely available at http://wwwsolar.nrl.navy.mil/ chianti

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“…In this paper, we used collision strengths and Υ values for Ca  and Fe  calculated by Kimura et al (2000) with the relativistic R-matrix code, in which resonances are included by a close-coupling formalism. Further details are given by Rainnie (2002) and by Harra-Murnion et al (1996) who used R-matrix atomic data for the case of S  lines w − z.…”

Section: Solar Flare Fe XXV and Ca Xix Spectramentioning

confidence: 99%

Improved data for solar flare X-ray spectral analysis

Phillips

Rainnie

Harra

et al. 2004

A&A

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Abstract. The inclusion of collisional rates for He-like Fe and Ca ions is discussed with reference to the analysis of solar flare Fe  and Ca  line emission, particularly from the Yohkoh Bragg Crystal Spectrometer (BCS). The new data are a slight improvement on calculations presently used in the BCS analysis software in that the discrepancy in the Fe  y and z line intensities (observed larger than predicted) is reduced. Values of electron temperature from satellite-to-resonance line ratios are slightly reduced (by up to 1 MK) for a given observed ratio. The new atomic data will be incorporated in the Yohkoh BCS databases. The data should also be of interest for the analysis of high-resolution, non-solar spectra expected from the Constellation-X and Astro-E space missions. A comparison is made of a tokamak S  spectrum with a synthetic spectrum using atomic data in the existing software and the agreement is found to be good, so validating these data for particularly high-n satellite wavelengths close to the S  resonance line. An error in a data file used for analyzing BCS Fe  spectra is corrected, so permitting analysis of these spectra.

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Rate coefficients for electron impact excitation of helium-like ions within the DiracR-matrix approach

Cited by 24 publications

References 29 publications

CHIANTI – An atomic database for emission lines. Version 8

CHIANTI – An atomic database for emission lines. Version 8

CHIANTI – an atomic database for emission lines

Improved data for solar flare X-ray spectral analysis

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