<i>R</i>-matrix electron-impact excitation data for the B-like iso-electronic sequence

Liang, G. Y.; Badnell, N. R.; Zhao, Gang

doi:10.1051/0004-6361/201220277

Cited by 62 publications

(112 citation statements)

References 33 publications

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“…A comparison with the energy levels of Liang et al (2012) is not possible since theoretical energies were only published for four ions (Ne 5+ , Ar 13+ , Fe 21+ and Kr 31+ ) along the B-like isoelectronic sequence.…”

Section: Target Modelmentioning

confidence: 99%

“…A constant mesh spacing of 2 × 10 −4 Ryd was utilised in the resonance region, similar to the 2.45 × 10 −4 Ryd mesh employed by Liang et al (2012). A total of 250 points were used in the coarse mesh region from 16.9-50 Ryd.…”

Section: Collision Calculationmentioning

confidence: 99%

“…In Sect. 3 a selection of collision strengths and effective collision strengths are presented for both models and compared with the results of Zhang et al (1994) and Liang et al (2012). Theoretical line intensities are calculated using CLOUDY C13 (Ferland et al 2013) in Sect.…”

Section: Introductionmentioning

confidence: 99%

“…Following the completion of our calculations, the recent work of Liang et al (2012) was kindly brought to our attention by the referee. Liang et al (2012) performed a series of intermediate-coupling frame transformation (ICFT) R-matrix calculations for the B-like iso-electronic sequence, including Mg .…”

Section: Introductionmentioning

confidence: 99%

“…Liang et al (2012) performed a series of intermediate-coupling frame transformation (ICFT) R-matrix calculations for the B-like iso-electronic sequence, including Mg . The calculation incorporated the additional n = 3 and n = 4 complexes, giving rise to a total of 204 fine structure levels.…”

Section: Introductionmentioning

confidence: 99%

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Electron impact excitation of Mg VIII

Grieve

Ramsbottom

Keenan

2013

A&A

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Context. Mg  emission lines are observed in a range of astronomical objects such as the Sun, other cool stars and in the coronal line region of Seyfert galaxies. Under coronal conditions Mg  emits strongly in the extreme ultraviolet (EUV) and soft X-ray spectral regions which makes it an ideal ion for plasma diagnostics. Aims. Two theoretical atomic models, consisting of 125 fine structure levels, are developed for the Mg  ion. The 125 levels arise from the 2s 2 2p, 2s2p 2 , 2p 3 , 2s 2 3s, 2s 2 3p, 2s 2 3d, 2s2p3s, 2s2p3p, 2s2p3d, 2p 2 3s, 2p 2 3p and 2p 2 3d configurations. Electron impact excitation collision strengths and radiative transition probabilities are calculated for both Mg  models, compared with existing data, and the best model selected to generate a set of theoretical emission line intensities. The EUV lines, covering 312-790 Å, are compared with existing solar spectra (SERTS-89 and SUMER), while the soft X-ray transitions (69-97 Å) are examined for potential density diagnostic line ratios and also compared with the limited available solar and stellar observational data. Methods. The R-matrix codes Breit-Pauli RMATRXI and RMATRXII are utilised, along with the PSTGF code, to calculate the collision strengths for two Mg  models. Collision strengths are averaged over a Maxwellian distribution to produce the corresponding effective collision strengths for use in astrophysical applications. Transition probabilities are also calculated using the CIV3 atomic structure code. The best data are then incorporated into the modelling code CLOUDY and line intensities generated for a range of electron temperatures and densities appropriate to solar and stellar coronal plasmas.Results. The present effective collision strengths are compared with two previous calculations. Good levels of agreement are found with the most recent, but there are large differences with the other for forbidden transitions. The resulting line intensities compare favourably with the observed values from the SERTS-89 and SUMER spectra. Theoretical soft X-ray emission lines are presented and several density diagnostic line ratios examined, which are in reasonable agreement with the limited observational data available.

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Section: Target Modelmentioning

confidence: 99%

Section: Collision Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electron impact excitation of Mg VIII

Grieve

Ramsbottom

Keenan

2013

A&A

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Solar UV and X-ray spectral diagnostics

Zanna

Mason

2018

Living Rev Sol Phys

222

139

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X-ray and ultraviolet (UV) observations of the outer solar atmosphere have been used for many decades to measure the fundamental parameters of the solar plasma. This review focuses on the optically thin emission from the solar atmosphere, mostly found at UV and X-ray (XUV) wavelengths, and discusses some of the diagnostic methods that have been used to measure electron densities, electron temperatures, differential emission measure (DEM), and relative chemical abundances. We mainly focus on methods and results obtained from high-resolution spectroscopy, rather than broad-band imaging. However, we note that the best results are often obtained by combining imaging and spectroscopic observations. We also mainly focus the review on measurements of electron densities and temperatures obtained from single ion diagnostics, to avoid issues related to the ionisation state of the plasma. We start the review with a short historical introduction on the main XUV high-resolution spectrometers, then review the basics of optically thin emission and the main processes that affect the formation of a spectral line. We mainly discuss plasma in equilibrium, but briefly mention non-equilibrium ionisation and non-thermal electron distributions. We also summarise the status of atomic data, which are an essential part of the diagnostic process. We then review the methods used to measure electron densities, electron temperatures, the DEM, and relative chemical abundances, and the results obtained for the lower solar atmosphere (within a fraction of the solar radii), for coronal holes, the quiet Sun, active regions and flares.

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Energy levels, transition rates and electron impact excitation rates for B-like Kr XXXII

et al. 2020

Atomic Data and Nuclear Data Tables

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Energy levels and transition rates for electric-dipole, electric-quadrupole, electric-octupole, magnetic-dipole, and magneticquadrupole transitions among the levels arising from the n ≤ 5 configurations in B-like Kr XXXII are calculated by using two state-of-the-art methods, namely, the multi-configuration Dirac-Hartree-Fock (MCDHF) approach and the second-order many-body perturbation theory (RMBPT). Our results are compared with several available experimental and other theoretical values. Electron-impact excitation (EIE) collision strengths are calculated via the independent process and isolated resonance approximation using distorted-wave (denoted by IPIRDW). Radiation damping effects on the resonance excitation contributions are included. Effective collision strengths are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Spectral line intensities are modeled by using collision radiative model, and several line pairs pointed out might be useful for density diagnostics.It is well known that atomic spectroscopy of highly-charged ions is of particular interest for plasma control and plasma diagnostics on chemical composition, electron density and temperature, and electric and magnetic fields. Krypton, as a rare gas, has been widely used in diagnosing tokamak fusion plasmas [1-3], since it does not pollute the vacuum vessel and is easily introduced into the plasmas. Furthermore, due to its almost ideal ionization balance and ease of injection, krypton has been the prime candidate for core Doppler spectroscopy on ITER [4][5][6]. Atomic data (including energy levels, transition rates, collision strengths, etc.) are required for many krypton ions. Recently, we reported accurate level energies, transition parameters and lifetimes for Kr XXIV [7], Kr XXV [8] and Kr XXVII -Kr XXXI [9-13], using both the RMBPT approach and MCDHF method. This work reports our efforts for B-like Kr XXXII.The experimental studies on B-like Kr were very limited [1,2,[14][15][16][17], and only 11 n = 2 levels have been compiled by the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST) [18]. Most of the existing theoretical calculations were confined to the n = 2 and n = 3 configurations [19-28]. Of particular note was the work presented by Aggarwal et al. [26], in which the Flexible Atomic Code (FAC) [29] and GRASP0 package [30] have been adopted to obtain level energies, lifetimes, wavelengths and transition rates for transitions among the lowest 125 levels of the n ≤ 3 configurations. In addition, Aggarwal et al. [31] also adopted the fully relativistic Dirac Atomic R-matrix Code (DARC) of Norrington and Grant to calculate collision strengths and effective collision strengths. Recently, Liang et al. [32] adopted Thomas-Femi-Dirac-Amaldi model potential from AUTOSTRUCTURE (AS) [33] to calculate the energy levels, line strengths and lifetimes for the 204 n ≤ 4 energy levels of several B-like ions including Kr XXXII. Meanwhile, Liang et al. [32] perf...

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

Cited by 62 publications

References 33 publications

Electron impact excitation of Mg VIII

Electron impact excitation of Mg VIII

Solar UV and X-ray spectral diagnostics

Energy levels, transition rates and electron impact excitation rates for B-like Kr XXXII

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