Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities: An Experimenter’s View

Trabert, E

doi:10.3390/atoms2010015

Cited by 25 publications

(16 citation statements)

References 275 publications

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“…The red line indicates the value obtained from ab-initio calculations, adjusted to the experimental transition energy. The blue line indicates the value obtained by additionally taking into account the anomalous magnetic moment of the electronImage reproduced with permission from Träbert (2014a)…”

Section: Atomic Calculations and Datamentioning

confidence: 99%

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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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Section: Atomic Calculations and Datamentioning

confidence: 99%

“…This offers an excellent way to benchmark/validate the atomic structure calculations. For general reviews of how atomic structure calculations can be assessed by, e.g., lifetime measurements see, e.g., Träbert (2010, 2014a). Träbert (2005) reviewed lifetime measurements for the important iron ions.…”

Section: Atomic Calculations and Datamentioning

confidence: 99%

Solar UV and X-ray spectral diagnostics

Zanna

Mason

2018

Living Rev Sol Phys

222

139

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“…For radiative rates, on the order hand, there are fewer experimental results and the benchmarking of theoretical methods has been performed with ions other than neonlike [87][88][89][90][91]; a very few cases where neonlike high-Z ions were studied [92,93] are the exception. (There also have been studies of transition rates in low-Z ions of the Ne isoelectronic sequence, with reviews that illustrate the pitfalls of experiment and calculation [94][95][96]). Thus, theoretical radiative rates in neonlike ions often differ considerably when calculated with various theoretical methods [40,52,[58][59][60]64] even while excitation energies may be in good agreement.…”

Section: Calculationmentioning

confidence: 99%

Electron-correlation effects on the3Cto3Dline-intensity ratio in the Ne-like ionsAr8+
Santana
¹
,
Lepson
²
,
Beiersdörfer
³

2015
Phys. Rev. A
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30
5
21
0
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We present a theoretical and experimental investigation of the 3d → 2p resonance to intercombination line ratio in low-to mid-Z neonlike ions of astrophysical interest, i.e., of the 2p 1/2 2p 4 3/2 3d 3/2 1 P o 1 → 2p 6 1 S 0 and 2p 2 1/2 2p 3 3/2 3d 5/2 3 D o 1 → 2p 6 1 S 0 transitions commonly labeled 3C and 3D, respectively. In particular, we have employed the configuration interaction method with three different numbers of basis states and the many-body perturbation theory method to calculate oscillator strengths and energies for neonlike ions from Z = 18 to Z = 36. Combining our calculations with a systematic study of previous works in the literature, we show that these methods can predict accurate and converged energies for these transitions. We also find convergence for the oscillator strengths, but the ratio of oscillator strengths, which can be compared to experimental values of the relative intensity ratios of these lines, appears to converge to values higher than measured. We speculate that this is due to the role of electron-electron correlations. While the amount of electron correlations associated with the intercombination line 3D appears to be well described, it seems that the contributions from highly excited states are not sufficiently accounted for in the case of the resonance line 3C. In order to augment the body of available experimental data for neonlike ions, we present a measurement of the 3C and 3D lines in neonlike Ar 8+. We report a wavelength of 41.480 ± 0.001Å for line 3C and 42.005 ± 0.001Å for line 3D. The intensity ratio of the two lines was determined to be I(3C)/I(3D) = 11.32 ± 1.40.

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“…For highly charged ions, there are few experimental methods available to determine transition rates. Lifetimes for long-lived states of the ground configuration or the lowest excited configurations have been determined in accurate storage-ring and trapping experiments (see for example, the review by Träbert [59]) and are used for benchmarking. Lifetimes for a large range of short-lived states have been determined using beam-foil spectroscopy [60].…”

Section: Transition Probabilitiesmentioning

confidence: 99%

Multiconfiguration Dirac-Hartree-Fock Calculations with Spectroscopic Accuracy: Applications to Astrophysics

Jönsson

Gaigalas

Rynkun

et al. 2017

Atoms

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Abstract:Atomic data, such as wavelengths, spectroscopic labels, broadening parameters and transition rates, are necessary for many applications, especially in plasma diagnostics, and for interpreting the spectra of distant astrophysical objects. The experiment with its limited resources is unlikely to ever be able to provide a complete dataset on any atomic system. Instead, the bulk of the data must be calculated. Based on fundamental principles and well-justified approximations, theoretical atomic physics derives and implements algorithms and computational procedures that yield the desired data. We review progress and recent developments in fully-relativistic multiconfiguration Dirac-Hartree-Fock methods and show how large-scale calculations can give transition energies of spectroscopic accuracy, i.e., with an accuracy comparable to the one obtained from observations, as well as transition rates with estimated uncertainties of a few percent for a broad range of ions. Finally, we discuss further developments and challenges.

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Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities: An Experimenter’s View

Cited by 25 publications

References 275 publications

Solar UV and X-ray spectral diagnostics

Solar UV and X-ray spectral diagnostics

Electron-correlation effects on the3Cto3Dline-intensity ratio in the Ne-like ionsAr8+
Santana
¹
,
Lepson
²
,
Beiersdörfer
³

2015
Phys. Rev. A
Self Cite
30
5
21
0
View full text Add to dashboard Cite

Multiconfiguration Dirac-Hartree-Fock Calculations with Spectroscopic Accuracy: Applications to Astrophysics

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Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities: An Experimenter’s View

Cited by 25 publications

References 275 publications

Solar UV and X-ray spectral diagnostics

Solar UV and X-ray spectral diagnostics

Electron-correlation effects on the3Cto3Dline-intensity ratio in the Ne-like ionsAr8+Santana1, Lepson2, Beiersdörfer3 2015Phys. Rev. ASelf Cite305210View full textAdd to dashboardCite

Multiconfiguration Dirac-Hartree-Fock Calculations with Spectroscopic Accuracy: Applications to Astrophysics

Contact Info

Product

Resources

About

Electron-correlation effects on the3Cto3Dline-intensity ratio in the Ne-like ionsAr8+
Santana
¹
,
Lepson
²
,
Beiersdörfer
³

2015
Phys. Rev. A
Self Cite
30
5
21
0
View full text Add to dashboard Cite