Discrepancies in Atomic Data and Suggestions for Their Resolutions

Aggarwal, K. M.

doi:10.3390/atoms5040037

Cited by 22 publications

(34 citation statements)

References 82 publications

(180 reference statements)

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“…Combined with our earlier results [2][3][4][5][6][7][8]18], along with those of Si et al [9] and Li et al [10], the present work completes data for all F-like ions with Z ≤ 74. These works include a larger number of levels than generally available in the literature, are comparatively more accurate, and hence can be confidently and reliably applied in the diagnostics and modelling of a variety of plasmas, including astrophysical and fusion.…”

Section: Discussionsupporting

confidence: 89%

“…Also included in these tables are the results from the MCHF calculations of Froese Fischer and Tachiev [16], but only for the lowest 60 levels. It may be noted that the results for Sc XIII are not included here (or in subsequent tables), because these have already been discussed in a separate paper [18]. Finally, as already stated and demonstrated in earlier works, with the inclusion of same CI there are no appreciable discrepancies in energies (for most of the levels) obtained from the GRASP and FAC codes.…”

Section: Energy Levelsmentioning

confidence: 88%

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Radiative rates for E1, E2, M1, and M2 transitions in F-like ions with 12 ≤ Z ≤ 23

Aggarwal

2019

Atomic Data and Nuclear Data Tables

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In this paper, energy levels, radiative rates and lifetimes are reported for 11 F-like ions with 12 ≤ Z ≤ 23. Up to 198 levels (depending on the ion) have been considered which include 113 of the 2s 2 2p 5 , 2s2p 6 , 2s 2 2p 4 3ℓ, 2s2p 5 3ℓ, and 2p 6 3ℓ configurations. The general-purpose relativistic atomic structure package (grasp) and the flexible atomic code (fac) have been adopted for calculating the energy levels, but the grasp alone for the remaining parameters. Radiative rates (along with oscillator strengths and line strengths) are listed for all E1, E2, M1, and M2 transitions of the ions.Comparisons are made with earlier available theoretical and experimental energies, for all ions, in order to assess the accuracy of the calculations. Comparisons have also been made for the radiative rates and lifetimes, which have been possible for only those among the lowest 60 levels.

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Section: Discussionsupporting

confidence: 89%

Section: Energy Levelsmentioning

confidence: 88%

Radiative rates for E1, E2, M1, and M2 transitions in F-like ions with 12 ≤ Z ≤ 23

Aggarwal

2019

Atomic Data and Nuclear Data Tables

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“…If a code is incorrectly and/or non-judicially applied then large discrepancies may occur, as demonstrated in this paper. A number of large discrepancies, for several atomic parameters, have been noted earlier for many ions, and these have been highlighted in our recent paper [5], along with suggestions for their resolutions.…”

Section: Discussionsupporting

confidence: 59%

Comment on “Collision strength and effective collision strength for Ba XLVIII” by Mohan et al. [Can. J. Phys. 95, 173 (2017)]

Aggarwal

2018

Can. J. Phys.

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In a recent paper, Mohan et al. [Can. J. Phys. 95 (2017) 173] have reported results for collision strengths (Ω) and effective collision strengths (Υ) for transitions from the ground to higher 51 excited levels of F-like Ba XLVIII. For the calculations of Ω, the Dirac atomic R-matrix code (DARC) and the flexible atomic code (FAC) have been adopted, in order to facilitate a direct comparison. However, for the subsequent calculations of Υ, DARC alone has been employed. In this comment, we demonstrate that while their limited results for Ω are comparatively reliable, for Υ are not, particularly for the allowed transitions and at lower temperatures. Apart from the non expected behaviour, their Υ values are overestimated for several transitions, by about a factor of two.

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“…We adopted Υ ij from Anderson et al (2002) when the orbital quantum number of the bound states are specified, and from Przybilla & Butler (2004) otherwise. For collisions between degenerate states 2p 2 P * 1/2 −2s 2 S 1/2 and 2s 2 S 1/2 −2p 2 P * 3/2 , we adopted the Υ ij reported by Aggarwal et al (2018).…”

Section: Collisional Processesmentioning

confidence: 99%

Rapid Escape of Ultra-hot Exoplanet Atmospheres Driven by Hydrogen Balmer Absorption

Muñoz

Schneider

2019

ApJL

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Atmospheric escape is key to explaining the long-term evolution of planets in our Solar System and beyond, and in the interpretation of atmospheric measurements. Hydrodynamic escape is generally thought to be driven by the flux of extreme ultraviolet photons that the planet receives from its host star. Here, we show that the escape from planets orbiting hot stars proceeds through a different yet complementary process: drawing its energy from the intense near ultraviolet emission of the star that is deposited within an optically thin, high-altitude atmospheric layer of hydrogen excited into the lower state of the Balmer series. The ultra-hot exoplanet KELT-9b likely represents the first known instance of this Balmer-driven escape. In this regime of hydrodynamic escape, the near ultraviolet emission from the star is more important at determining the planet mass loss than the extreme ultraviolet emission, and uncertainties in the latter become less critical. Further, we predict that gas exoplanets around hot stars may experience catastrophic mass loss when they are less massive than 1-2 Jupiter masses and closer-in than KELT-9b, thereby challenging the paradigm that all large exoplanets are stable to atmospheric escape. We argue that extreme escape will affect the demographics of close-in exoplanets orbiting hot stars.

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Discrepancies in Atomic Data and Suggestions for Their Resolutions

Cited by 22 publications

References 82 publications

Radiative rates for E1, E2, M1, and M2 transitions in F-like ions with 12 ≤ Z ≤ 23

Radiative rates for E1, E2, M1, and M2 transitions in F-like ions with 12 ≤ Z ≤ 23

Comment on “Collision strength and effective collision strength for Ba XLVIII” by Mohan et al. [Can. J. Phys. 95, 173 (2017)]

Rapid Escape of Ultra-hot Exoplanet Atmospheres Driven by Hydrogen Balmer Absorption

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