Excitation energies and transition rates in magnesiumlike ions

Safronova, U. I.; Johnson, W. R.; Berry, H. G.

doi:10.1103/physreva.61.052503

Cited by 77 publications

(112 citation statements)

References 45 publications

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“…Gauge-independent second-order relativistic MBPT calculations of matrix elements for Be-like and Mg-like ions were carried out in Refs. [63] and [64], respectively.…”

Section: Mbpt For Atoms With Two Valence Electronsmentioning

confidence: 99%

All-Order Methods for Relativistic Atomic Structure Calculations

Safronova¹,

Johnson²

2008

Advances in Atomic, Molecular, and Optical Physics

116

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All-order extensions of relativistic atomic many-body perturbation theory are described and applied to predict properties of heavy atoms. Limitations of relativistic many-body perturbation theory are first discussed and the need for all-order calculations is established. An account is then given of relativistic all-order calculations based on a linearized version of the coupled-cluster expansion. This account is followed by a review of applications to energies, transition matrix elements, and hyperfine constants. The need for extensions of the linearized coupled-cluster method is discussed in light of accuracy limits, the availability of new computational resources, and precise modern experiments. For monovalent atoms, calculations that include nonlinear terms and triple excitations in the coupled-cluster expansion are described. For divalent atoms, results from second-and third-order perturbation theory calculations are given, along with results from configuration-interaction calculations and mixed configuration interaction-many-body perturbation theory calculations. Finally, applications of all-order methods to atomic parity nonconservation, polarizabilities, C 3 and C 6 coefficients, and isotope shifts are given.

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“…Gauge-independent second-order relativistic MBPT calculations of matrix elements for Be-like and Mg-like ions were carried out in Refs. [63] and [64], respectively.…”

Section: Mbpt For Atoms With Two Valence Electronsmentioning

confidence: 99%

All-Order Methods for Relativistic Atomic Structure Calculations

Safronova¹,

Johnson²

2008

Advances in Atomic, Molecular, and Optical Physics

116

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“…We have compared results for the forbidden transitions from metastable levels in the 3s3p configuration, and allowed transitions giving rise to the strongest lines in the Ca IX spectrum. The forbidden transitions from the 3s3p calculation to the ground level show very good agreement (within 20%, mostly down to 5%) amongst all calculations, with the only [9] (observed); F83: Fawcett [16]; C86: Christensen et al [18]; S00: Safronova et al [25]; FF06: Froese Fischer et al [21]; K04: Karpuskiene et al [27]; T05: Tayal [24]. Transition FAC SST F83 C86 T86 T05 ZFF01 A10 T98 FF06 K04 K10 [18] underestimate by a factor 7 the A value for transition 5-6, giving rise to the line at 821Å observed by SUMER in the solar spectrum (Curdt et al [7]); a factor 4 difference also separates the Christensen et al [18] A value for the important 1-3 transition (giving rise to the observed 691Å spectral line) from all other results.…”

Section: Assessment Of Resultsmentioning

confidence: 99%

“…These calculations have been carried out by a number of authors using different techniques and atomic model (Fawcett [16], Kastner et al [17], Christensen et al [18], Tayal [19], Godefroid [20], Froese Fischer et al [21], Stanek et al [22], Zou & Froese Fischer [23], Tayal [24], Safronova et al [25], Aashamar [26], Karpuskiene et al [27]). Most of the calculations provided data only for levels in the n = 3 complex, but a few of them also included some n = 4 levels (Kastner et al [17], Christensen et al [18], Froese Fischer et al [21], Aashamar [26], Karpuskiene et al [27] and Tayal [24]).…”

Section: Introductionmentioning

confidence: 99%

Atomic data and spectral line intensities for Ca IX

Landi

Bhatia

2014

Atomic Data and Nuclear Data Tables

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Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for Ca IX. We include in the calculations the 33 lowest configurations in the n = 3, 4, 5 complexes, corresponding to 283 fine structure levels in the 3l3l ′ , 3l4l ′′ and 3l4l ′′′ configurations, whereCollision strengths are calculated at five incident energies for all transitions: 5.8, 13.6, 24.2, 38.6 and 57.9 Ry above the threshold of each transition. An additional energy, very close to the transition threshold, has been added, whose value is between 0.0055 Ry and 0.23 Ry depending on the levels involved. Calculations have been carried out using the Flexible Atomic Code and the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates calculated in the present work, statistical equilibrium equations for level populations are solved at electron densities covering the 10 8 -10 14 cm −3 range and at an electron temperature of log T e (K)=5.8, corresponding to the maximum abundance of Ca IX. Spectral line intensities are calculated, and their diagnostic relevance is discussed.

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“…In addition to the calculations above, see for example, Safronova et al (2000), Froese Fischer et al (2006), Massacrier & Artru (2012), Hu et al (2014), Si et al (2015), Santana & Träbert (2015). The most recent R-matrix calculations for the Mg-like ions include both collisional and radiative data (Fernandez-Menchero et al 2014).…”

Section: Introductionmentioning

confidence: 99%

MCDHF and RCI calculations of energy levels, lifetimes and transition rates for3l3l′,3l4l′, and3s5lstates in Ca IX – As XXII and Kr XXV

Gustafsson

Jönsson

Fischer

et al. 2017

A&A

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Multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and relativistic configuration interaction (RCI) calculations were performed for states of the 3l3l , 3l4l and 3s5l configurations in the Mg-like ions Ca IX -As XXII and Kr XXV. Valence and core-valence electron correlation effects are accounted for through large configuration state function expansions. Calculated excitation energies are in very good agreement with observations for the lowest levels. For higher lying levels observations are often missing and present energies aid line identification in spectra. Lifetimes and transition data are given for all ions. There is an excellent agreement for both lifetimes and transition data with recent multiconfiguration Hartree-Fock Breit Pauli calculations.

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Excitation energies and transition rates in magnesiumlike ions

Cited by 77 publications

References 45 publications

All-Order Methods for Relativistic Atomic Structure Calculations

All-Order Methods for Relativistic Atomic Structure Calculations

Atomic data and spectral line intensities for Ca IX

MCDHF and RCI calculations of energy levels, lifetimes and transition rates for3l3l′,3l4l′, and3s5lstates in Ca IX – As XXII and Kr XXV

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