Emission‐Line Spectra of Ar<scp>ix</scp>–Ar<scp>xvi</scp>in the Soft X‐Ray Region 20–50 A

Lepson, J. K.; Beiersdörfer, P.; Behar, E.; Kahn, S. M.

doi:10.1086/374980

Cited by 82 publications

(102 citation statements)

References 23 publications

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“…(a) Sources of NIST v3 are from the unpublished work of Shirai et al (1999), and references therein, while that of CHIANTI v6 is from the work of Lepson et al (2003).…”

Section: Notesmentioning

confidence: 99%

R-matrix electron-impact excitation data for the Ne-like iso-electronic sequence

Liang

Badnell²

2010

A&A

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We present results for the electron-impact excitation of all Ne-like ions from Na + to Kr 26+ obtained using the intermediate-coupling frame transformation R-matrix approach. For each ion's calculation, the close-coupling expansion is taken to be the 113 LS terms (209 levels) belonging to the configurations [1s 2 ]2s 2 2p 6 , 2s 2 2p 5 {3, 4, 5}l, 2s2p 6 {3, 4, 5}l (l ∈ s, p, d, f, and g), and 2s 2 2p 5 {6, 7}l (l ∈ s, p, and d). An additional configuration interaction effect arising from configurations of 2s 2 2p 4 3l{3, 4, 5}l (l ∈ s, p, d, f and g) was included in the target expansion. A detailed comparison of the target structure has been made for six specific ions (Si 4+ , Ar 8+ , Ca 10+ , Fe 16+ , Ni 18+ , and Kr 26+ ) spanning the sequence to assess the accuracy for the entire sequence. Effective collision strengths (Υs) are presented at temperatures ranging from 2×10 2 (q+1) 2 K to 2×10 6 (q+1) 2 K (where q is the residual charge of ions, i.e. Z −10). Detailed comparisons for the Υs are made with the results of previous calculations for several ions, which span the sequence. Furthermore, we examine the iso-electronic trends of effective collision strengths as a function of temperature. The present results are the only R-matrix ones for the majority of the ions and the most extensive and complete data for modelling to-date.

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“…(a) Sources of NIST v3 are from the unpublished work of Shirai et al (1999), and references therein, while that of CHIANTI v6 is from the work of Lepson et al (2003).…”

Section: Notesmentioning

confidence: 99%

R-matrix electron-impact excitation data for the Ne-like iso-electronic sequence

Liang

Badnell²

2010

A&A

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“…In Table 2 Table 2. Therefore, a larger calculation has become necessary, especially when some of the observed emission lines belong to the 4 levels -see Table 6 of Lepson et al (2003).…”

Section: Ar XIVmentioning

confidence: 99%

“…A complete list of lines over a wide range of wavelengths for many ions, including those of argon, are available in the  database at http://wwwsolar.nrl.navy.mil/chianti.html. Additionally, to provide experimental support to observational data, many lines of Ar IX−XVI in the 20−50 Å X-ray range have been measured in the electron beam ion trap () experiments of the Lawrence Livermore National Laboratory (Lepson et al 2003). …”

Section: Introductionmentioning

confidence: 99%

Energy levels and radiative rates for transitions in Ar XIII, Ar XIV and Ar XV

Aggarwal¹,

Keenan²,

Nakazaki

2005

A&A

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Abstract. Energies for 524 levels of Ar XIII, 460 levels of Ar XIV and 156 levels of Ar XV have been calculated using the  code of Dyall et al. (1989). Additionally, radiative rates, oscillator strengths, and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among these levels. Comparisons are made with the limited results available in the literature, and the accuracy of the data is assessed. Our energy levels are estimated to be accurate to better than 1%, whereas results for other parameters are probably accurate to better than 20%. Additionally, the level lifetimes derived from our radiative rates are in excellent agreement with measured values.

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“…For example, Audard et al (2001) demonstrated the discrepancies between modelling and the XMM-Newton observation for Capella, in particular emission lines in range of 20−38 Å. In modelling laboratory spectroscopy of highly-charged argon and sulphur with the Hebrew University Lawrence Livermore Atomic Code (HULLAC; Bar-Shalom et al 1988), Lepson et al (2003Lepson et al ( , 2005 demonstrated that there are large discrepancies between the laboratory measurements and the HULLAC simulation. Liang et al (2008b) reported a line list for highly charged Si ions including Si X, and their comparison with observed values for the Procyon corona showing discrepancies.…”

Section: Introductionmentioning

confidence: 99%

R-matrix electron-impact excitation data for B-like Si and its application in cool stars

Liang

Whiteford

Badnell³

2009

A&A

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We present the results of an intermediate coupling frame-transformation R-matrix calculation for the electron-impact excitation of Si 9+ . The target and close-coupling expansions are both taken to be the 125 fine-structure levels (58 LS terms) belonging to the configurations 2s x 2p y (x + y = 3) and 2s α 2p β 3l (α+ β = 2, l = s, p, and d). Due to the additional resonances included in our calculation, we find significant differences at low temperatures with the widely used n = 2 → 2 excitation rates, also obtained with the R-matrix method, as well as with the n = 2 → 3 excitation rates calculated by using the distorted wave (DW) approximation. We present a list of prominent transition lines and comparisons with SERTS and Hinode/EIS EUV spectra of the solar corona, SUMER observations for the quiet sun, as well as Chandra LETG and Rocket soft X-ray spectra of the Procyon corona and solar flares, respectively. Line emissivities of some transitions are enhanced up to 40% when compared with those obtained from using the previous atomic data at the same electron density (1.6 × 10 9 cm −3 ) and temperature (1.3 × 10 6 K). The comparison with Chandra LETG observation of Procyon reveals that the 3s−2p line flux was significantly underestimated (by a factor of 4−5) in previous analyses. Some EUV and soft X-ray emission line ratios are n e -sensitive and T e -insensitive. Estimated electron densities from them shift downwards due to the new resonant-enhanced excitation data used in the present modelling.

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Emission‐Line Spectra of Arix–Arxviin the Soft X‐Ray Region 20–50 A

Cited by 82 publications

References 23 publications

R-matrix electron-impact excitation data for the Ne-like iso-electronic sequence

R-matrix electron-impact excitation data for the Ne-like iso-electronic sequence

Energy levels and radiative rates for transitions in Ar XIII, Ar XIV and Ar XV

R-matrix electron-impact excitation data for B-like Si and its application in cool stars

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