Journal of Quantitative Spectroscopy & Radiative Transfer 314 (2024) 108867 Available online 6 December 2023 0022-4073/© 2023 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Journal of Quantitative Spectroscopy and Radiative Transfer journal homepage: www.elsevier.com/locate/jqsrt Quantum Stark widths of Se III–VI lines R. Aloui a , H. Elabidi b,∗ , S. Sahal-Bréchot c , M.S. Dimitrijevié c,d , R. Hamdi e , W. Belhadj b a Laboratoire Dynamique Moléculaire et Matériaux Photonique, Ecole Nationale Supérieurs d’Ingénieurs de Tunis, University of Tunis, Tunisia b Department of Physics, College of Sciences, Umm Al-Qura University, Makkah Almukarramah, 24382, Saudi Arabia c Observatoire de Paris, PSL University, Sorbonne Université, CNRS, LERMA, 92190 Meudon, France d Astronomical Observatory, Volgina 7, 11060 Belgrade, Serbia e College of Al-Qunfudah Health Sciences, Umm Al-Qura University, Makkah Almukarramah, Saudi Arabia ARTICLE INFO Keywords: Line profiles-atomic data-atomic processes-white dwarfs ABSTRACT Stark broadening for 19 spectral lines of several selenium ions (four Se III lines, eight Se IV lines, three Se V lines and four Se VI lines) have been calculated using our quantum mechanical method. Many lines among them have been recently discovered for the first time in the ultraviolet spectrum of the hot white dwarf (WD) RE 0503−289 and in the atmospheres of the cool DO white dwarfs HD 149499 B and HZ 21. This recent discovery prompts us to calculate the Stark widths of the new lines. Stark widths of only three Se III lines have been compared to the available modified semi-empirical results. We could not find Stark broadening data for the other considered lines. Two calculation stages are carried out before the Stark broadening evaluation: we calculate the atomic structure as a first step, and then we calculate the collision electron–ion as a second step. We present our results for the considered lines at different temperature values and at an electron density   = 10 17 cm −3 . The obtained results are useful for the modelling of stellar atmospheres. They will also enter the database of Stark broadening parameters: STARK-B. 1. Introduction Among the data needed for the analysis and interpretation of the spectra is the broadening of spectral lines in addition to the atomic structure of the emitter. The improvement of computers help us to calculate the atomic structure of very heavy elements [1–4]. The lack of atomic data of highly charged ions can obstruct the abundance determination of these elements. Stark widths results help to diagnose astrophysical plasma, to evaluate the radiative transfer and the stellar opacity [5]. Spectral lines can be broadened by Doppler, natural, Van der Waals, resonance or Stark effects. Our work is dedicated to the Stark broadening which is the most important for different densities and temperatures and for many astrophysical objects, such as white dwarfs. Recently, we showed that Stark broadening is important in hot white dwarf atmospheres [6,7], in hot star atmospheres [8], in white dwarfs of types DA and DB [9], and in DO white dwarfs [10]. In our work, we investigate four selenium ions: Se III, Se IV, Se V and Se VI. The present calculations can help for the study of their abundance in the atmospheres of the white dwarfs. The number of the previous publications shows the importance of these ions: Several papers [11–16] studied the Se III ion, Badami and Rao [11] investigated the spectrum of selenium Se III, Popović and Dimitrijević [12], Simić ∗ Corresponding author. E-mail address: haelabidi@uqu.edu.sa (H. Elabidi). et al. [13] studied the Stark broadening of doubly ionized atoms of Se III, Tauheed and Hala [14] performed revised and extended analyses of Se III, Macaluso et al. [15] studied – experimentally and theoretically – the absolute single-photoionization cross sections of Se III, and Sterling et al. [16] identified near-infrared doubly charged selenium emission lines in planetary nebulae. Bahr et al. [17], Gautam and Joshi [18] studied the spectrum of Se IV, Pakalka et al. [19] studied the electron-impact single ionization of the Se IV ion and Dimitrijević et al. [20] computed the Stark line widths of several ions including Se IV, but between -terms (without fine structure effects). We also found many works that investigated the Se V and Se VI ions: Sawyer and Humphereys [21] investigated the 29 and the 30 electron-system spectra of arsenic and selenium (Se V and Se VI), Joshi and Kleef [22] investigated the sixth spectrum of selenium ion (Se VI), Joshi [23] performed extended analyses of Se V and Se VI ions, Churilov and Joshi [24] studied the spectrum of the Se V ion. Se III-VI have been observed [25–27] via their spectral lines in the ultraviolet spectrum of RE 0503−289 and in the atmospheres of the cool DO white dwarfs HD 149499 B and HZ 21. The inaccuracy or the absence of line widths can affect the spectral analysis [28]. In this work, we limit our study to the only observed lines of Se III-VI ions: four Se III lines, eight Se IV lines, three Se V lines and four https://doi.org/10.1016/j.jqsrt.2023.108867 Received 30 September 2023; Received in revised form 2 December 2023; Accepted 4 December 2023