Spectral investigation of doubly ionized rubidium (Rb III) from relativistic Hartree-Fock calculations

Zhang, Wei; Palmeri, P.; Quinet, Pascal

doi:10.1140/epjd/e2014-50071-1

Cited by 3 publications

(3 citation statements)

References 35 publications

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“…The upper limit derived from the non-detection of very weak predicted Sc III and V III lines are next to meaningless for both stars. Zhang et al (2014) provided atomic data for Rb III. However, because these lines have never been observed, their positions are likely not accurate.…”

Section: Discussionmentioning

confidence: 99%

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Dorsch

Latour

Heber

et al. 2020

A&A

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Hot subdwarf stars of spectral types O and B represent a poorly understood phase in the evolution of low-mass stars, in particular of close compact binaries. A variety of phenomena are observed, which make them important tools for several astronomical disciplines. For instance, the richness of oscillations of many subdwarfs are important for asteroseismology. Furthermore, hot subdwarfs are among the most chemically peculiar stars known. Two intermediate He-rich hot subdwarf stars, LS IV–14°116 and Feige 46, are particularly interesting, because they show extreme enrichments of heavy elements such as Ge, Sr, Y, and Zr, which are strikingly similar in both stars. In addition, both stars show light oscillations at periods incompatible with standard pulsation theory and form the class of V366 Aqr variables. We investigated whether the similar chemical compositions extend to more complete abundance patterns in both stars and validate the pulsations in Feige 46 using its recent TESS light curve. High-resolution optical and near-ultraviolet spectroscopy are combined with non-local thermodynamical-equilibrium model atmospheres and synthetic spectra calculated with TLUSTY and SYNSPEC to consistently determine detailed metal abundance patterns in both stars. Many previously unidentified lines were identified for the first time with transitions originating from Ga III, Ge III-IV, Se III, Kr III, Sr II-III, Y III, Zr III-IV, and Sn IV, most of which have not yet been observed in any star. The abundance patterns of 19 metals in both stars are almost identical, light metals being only slightly more abundant in Feige 46, while Zr, Sn, and Pb are slightly less enhanced compared to LS IV–14°116. Both abundance patterns are distinctively different from those of normal He-poor hot subdwarfs of a similar temperature. The extreme enrichment in heavy metals of more than 4 dex compared to the Sun is likely the result of strong atmospheric diffusion processes that operate similarly in both stars while their similar patterns of C, N, O, and Ne abundances might provide clues to their as yet unclear evolutionary history. Finally, we find that the periods of the pulsation modes in Feige 46 are stable to better than Ṗ ≲ 10−8 s s−1. This is not compatible with Ṗ predicted for pulsations driven by the ɛ-mechanism and excited by helium-shell flashes in a star that is evolving, for example, onto the extended horizontal branch.

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Section: Discussionmentioning

confidence: 99%

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Dorsch

Latour

Heber

et al. 2020

A&A

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“…In order to fill in this gap, in the present paper, we report on calculations of oscillator strengths and transition probabilities in this ion performed using the HFR approach including corepolarization effects. This work is an extension of our recent investigations of the fifth row elements Rb III (Zhang et al 2014), Y II, Y III (Biémont et al 2011), Zr II (Malcheva et al 2006), Nb I (Malcheva et al 2011), Nb II, Nb III (Nilsson et al 2010), Mo II , Lundberg et al 2010, Jiang et al 2012, Tc II (Palmeri et al 2007), Ru I (Fivet et al 2009), Ru II, RuIII (Palmeri et al 2009), Rh II (Quinet et al 2011(Quinet et al , 2012, Rh III (Zhang et al 2013a), Pd I (Xu et al 2006), Pd III (Zhang et al 2013a), Ag II (Biémont et al 2005, Campos et al 2005, Ag III (Zhang et al 2013a), Sn I (Zhang et al 2008(Zhang et al , 2009(Zhang et al , 2010, Sb I (Hartman et al 2010), Te II and Te III (Zhang et al 2013b).…”

Section: Introductionmentioning

confidence: 62%

Atomic structure, radiative lifetime and oscillator strength calculations in doubly ionized molybdenum (Mo iii)

Quinet

2014

Phys. Scr.

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Radiative lifetimes, transition probabilities and oscillator strengths in doubly ionized molybdenum (Mo III) are reported for the first time in the present paper. This new set of atomic data has been obtained by using a semi-empirical computational technique based on the pseudorelativistic Hartree-Fock approach in which a large amount of intravalence and core-valence electron correlations were included. In view of the lack of theoretical and experimental data available in the literature for this ion, the reliability of the results obtained in our work is discussed on the basis of comparisons with the isoelectronic ion Nb II for which an investigation was recently performed using a similar method (Nilsson et al 2010 Astron. Astrophys. 511 A16).S Online supplementary data available from stacks.iop.org/ps/0/000000/mmedia

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“…During the past 5 years, we notably focused our work on the particular cases of Rb III (Z = 37), Mo III (Z = 42), Rh III (Z = 45), Pd III (Z = 46), Ag III (Z = 47), and Te III (Z = 52) for which no (or very few) radiative rates were available in the literature. For all these ions, the HFR + CPOL + CPEN method has been combined to a semi-empirical adjustment of radial parameters minimizing the differences between calculated energy levels and available experimental values to compute transition probabilities and oscillator strengths for a large number of spectral lines [69][70][71][72]. Because of the lack of radiative lifetime measurements, the quality of our calculations could only be estimated from isoelectronic comparisons, in particular from results we had formerly published in Nb II (isoelectronic of Mo III) [73], in Ru II (isoelectronic of Rh III) [74], and in Rh II (isoelectronic of Pd III) [75], for which similar HFR + CPOL + CPEN models revealed a very good agreement (generally within 10%) with accurate radiative lifetimes measured by means of the time-resolved laser-induced fluorescence technique.…”

Section: Fifth Row Elementsmentioning

confidence: 99%

Overview of recent advances performed in the study of atomic structures and radiative processes for the lowest ionization stages of heavy elements

Quinet

2017

Can. J. Phys.

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During the past 20 years, part of our work has been focused on the study of the atomic structure and the determination of radiative parameters in neutral and slightly ionized heavy atoms (Z ≥ 37). These elements attracted little previous interest because of the complexity of their electronic structures, the poor knowledge of their spectra, and the difficulty to perform experimental measurements. They present, however, great interest in the development of other scientific areas, such as astrophysics and plasma physics. In this paper, we give an overview of the recent progress performed by the group of Atomic Physics and Astrophysics at Mons University (Belgium) in the theoretical modelling and the experimental analysis of such heavy elements. We also discuss some applications of the atomic data obtained in our work for the interpretation of the spectra observed from astrophysical and laboratory plasmas.Key words: atomic data, oscillator strengths, radiative transition probabilities, heavy elements.Résumé : Durant les 20 dernières années, une partie de notre travail a été focalisée sur l'étude de la structure atomique et la détermination des paramètres radiatifs dans les atomes lourds neutres et faiblement ionisés (Z ≥ 37). Ces éléments avaient attiré peu d'intérêt auparavant à cause de la complexité de leurs structures électroniques, du manque de connaissance de leurs spectres et de la difficulté à réaliser des mesures expérimentales. Ils présentent cependant un grand intérêt pour le développe-ment d'autres domaines scientifiques comme l'astrophysique et la physique des plasmas. Dans cet article, nous présentons un aperçu général des progrès récents réalisés par le groupe de Physique Atomique et Astrophysique de l'Université de Mons (Belgique) dans la modélisation et l'analyse expérimentale de tels éléments lourds. Nous discutons également quelques applications des données atomiques obtenues dans notre travail pour l'interprétation des spectres observés à partir de plasmas astrophysiques et de laboratoire.Mots-clés : ions lourds, données atomiques, temps de vie radiatifs, forces d'oscillateur, probabilités de transition.

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Spectral investigation of doubly ionized rubidium (Rb III) from relativistic Hartree-Fock calculations

Cited by 3 publications

References 35 publications

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Atomic structure, radiative lifetime and oscillator strength calculations in doubly ionized molybdenum (Mo iii)

Overview of recent advances performed in the study of atomic structures and radiative processes for the lowest ionization stages of heavy elements

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