Variance of the distributions of energy levels and of the transition arrays in atomic spectra. III. Case of spin-orbit-split arrays

Bauche‐Arnoult, C.; Bauche, J.; Klapisch, M.

doi:10.1103/physreva.31.2248

Cited by 195 publications

(109 citation statements)

References 13 publications

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“…This good agreement applies to the relative strength of the relativistic sub-arrays whereas in Fig. 4 the SOSA model [3] yields good energies and variances for Tm +47 compared to the DLA results, but incorrect strength ratio of the relativistic sub-arrays (known limitation of SOSA approach [7,8]). In these examples the PRTA offers about 3 orders of magnitude savings in computational effort compared to the full DLA calculation (see Table 1).…”

Section: Calculation Detailsmentioning

confidence: 64%

“…This reflects that spin-orbit splitting contributes to the total array variance, but not to the individual relativistic sub-array variance [3].…”

Section: Rpta Model In Intermediate Couplingmentioning

confidence: 99%

“…1 through 4 display UTA calculations using the LS basis including the spinorbit interaction [2] as well as calculations with the spin-orbit split-array method [3] (here referred to as UTA-LS and SOSA, respectively). The figures show the PRTA in better agreement with DLA than either UTA approaches.…”

Section: Calculation Detailsmentioning

confidence: 99%

“…For complex ions, however, the myriad spectral lines make DLA calculations impractical [1]. One approach to circumvent this impasse is the unresolved transition array (UTA) model where the lines are treated as a single unresolved feature [2,3]. The UTA model gives compact formulas for the transition array strength-weighted energy mean and variance that together with a Gaussian assumption for the line energy-strength correlation function allows for a fast calculation of the spectrum.…”

Section: Introductionmentioning

confidence: 99%

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Statistical line-by-line model for atomic spectra in intermediate coupling

Iglesias

2012

High Energy Density Physics

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The partially resolved transition array (PRTA) model is extended from JJ to intermediate coupling. The PRTA model conserves known array properties, yields improved higher moments, and systematically accounts for initial level populations. In addition, a random PRTA (R-PRTA) model is proposed to simulate detailed line accounting (DLA) calculations of complex spectra.Numerical examples show that the PRTA model with intermediate coupling reproduces the effects of the electrostatic interaction between spin-orbit split arrays on the spectrum. They also show that the R-PRTA model is in good agreement with DLA results and accounts for systematic line coincidences across transition arrays differing only in the subshell occupation of excited spectator electrons important in opacity calculations. Both PRTA and R-PRTA models are computationally much faster than DLA calculations. Hence, the models can accelerate spectrum calculations without introducing significant uncertainties whenever the DLA method is considered arduous or impractical.

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Section: Calculation Detailsmentioning

confidence: 64%

“…This reflects that spin-orbit splitting contributes to the total array variance, but not to the individual relativistic sub-array variance [3].…”

Section: Rpta Model In Intermediate Couplingmentioning

confidence: 99%

Section: Calculation Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Statistical line-by-line model for atomic spectra in intermediate coupling

Iglesias

2012

High Energy Density Physics

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“…A DLA calculation is performed if possible and necessary for all the transition arrays starting from the configuration; DLA computations are carried out only for pairs of configurations giving rise to less than 800,000 lines. In other cases, transition arrays are represented by Gaussian profiles in the UTA (Unresolved Transition Array [22,23]) or SOSA (Spin-Orbit Split Array [24]) formalisms. If the Rydberg supershell contains at least one electron, then transitions starting from the super-configuration are taken into account by the Super Transition Array (STA) model [25].…”

Section: Radiative Opacitymentioning

confidence: 99%

Detailed Opacity Calculations for Astrophysical Applications

Pain

Gilleron

Comet

2017

Atoms

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Nowadays, several opacity codes are able to provide data for stellar structure models, but the computed opacities may show significant differences. In this work, we present state-of-the-art precise spectral opacity calculations, illustrated by stellar applications. The essential role of laboratory experiments to check the quality of the computed data is underlined. We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as well as X-ray emission spectroscopy experiments involving hot dense plasmas produced by ultra-high-intensity laser irradiation. The measured spectra are systematically compared with the fine-structure opacity code SCO-RCG. The focus is on iron, due to its crucial role in understanding asteroseismic observations of β Cephei-type and Slowly Pulsating B stars, as well as of the Sun. For instance, in β Cephei-type stars, the iron-group opacity peak excites acoustic modes through the "kappa-mechanism". Particular attention is paid to the higher-than-predicted iron opacity measured at the Sandia Z-machine at solar interior conditions. We discuss some theoretical aspects such as density effects, photo-ionization, autoionization or the "filling-the-gap" effect of highly excited states.

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Opacity calculations in X and XUV range using a detailed atomic code

Poirier

2018

Contributions to Plasma Physics

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Calculations of accurate opacities in X and XUV range are of high interest for several domains such as astrophysics or inertial fusion science. Such quantities may be investigated through laser-plasma interaction in the indirect-drive scheme. In this work absorption properties of such plasmas are analysed using the Flexible Atomic Code. Detailed and unresolved-transition-array modes are investigated, and some results obtained with the mixed mode recently developed are also proposed. For a carbon plasma the present approach agrees with the results obtained with the superconfiguration code SCO. Some results are provided about the X-ray opacity of nickel, and a comparison with data from a recent campaign on LULI 2000 facility is done. This comparison demonstrates that the Unresolved Transition Array approach may be insufficient, e.g., to determinate the accurate position and shape of the 2p-3d structure in nickel at about 25 eV. The case of non-electric-dipole-type transitions, such as magnetic dipole transitions is addressed. The electric-dipole and magnetic-dipole transitions are studied here in the case of the 3 * n complex of five tungsten ions, with charge states similar to those found in the tokamak divertors. It is demonstrated that the unresolved transition array formulas provide a fairly accurate description of the most important absorption structures, but fail to reproduce correctly the behavior of the opacity in the wings of these main structures.

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Variance of the distributions of energy levels and of the transition arrays in atomic spectra. III. Case of spin-orbit-split arrays

Cited by 195 publications

References 13 publications

Statistical line-by-line model for atomic spectra in intermediate coupling

Statistical line-by-line model for atomic spectra in intermediate coupling

Detailed Opacity Calculations for Astrophysical Applications

Opacity calculations in X and XUV range using a detailed atomic code

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