Identification of visible lines from multiply charged W8+ and W9+ ions

Abstract

We present the investigation of new visible lines for W 8+ and W 9+ from the spectra observed using an electron beam ion trap. The analysis is based on the collisional-radiative (CR) modeling with fine-structure sublevels population kinetics. To ensure the identification of lines done by the CR model, we have also performed the accurate calculation of transition energies and transition probabilities within multi configurational Dirac-Fock using the GRASP2018. In the spectrum, most of the observed lines are assigned as magnetic dipole (M1) transitions belonging to the first two lower-lying configurations of these ions.

Visible spectra of W8+ in an electron-beam ion trap

“…While this paper was under review, similar experimental and theoretical results for W 8+ have been published by Priti et al [65]. Our experimental values are in good agreement with theirs for the wavelengths, and the same assignments to these lines are obtained based on individual calculations by using different computational models.…”

“…In addition, our large-scale FAC calculations fit better with measurements (~0.88% deviation on average) than those reported in Ref. [65]. The more accurate theoretical results in our work also demonstrate the effective capture of electron correlations in complex atomic systems like W 8+ , especially for the important influence related to the 4d and 4f electron correlation.…”

Electron-impact ionization of W9+ and W10+

“…The EA contribution in the EISI of [Cd] 4f 14 5p5d involves 5s, 5p, 4f and 5d subshells. EA process of [Cd] 4f 14 5p5d can be expressed as 14 nl 5s 2 5p4f 13 5dnl 5s 2 4f 14 5dnl 5s5p4f 14 5dnl…”

“…5s 2 5p 2 4f 14 5s 2 5p 3 4f 13 5s5p 3 4f 14 5s 2 5p 2 4f 13 13 nl 5s 2 5p4f 14 nl 5s5p 2 4f 14 nl 5s 2 5p4f 14 nl 5s 2 5p4f 13 5dnl 5s 2 4f 14 5dnl 5s5p4f 14 5dnl…”

“…[12] Moreover, in a recent experiment, Yan et al observed the W 7+ line at 574.47 nm at 48 eV in the electron-beam ion trap (EBIT) plasma, which is far below the W 5+ (65 eV) and W 6+ (122 eV) ionization thresholds, confirmed the significantly contribution of the metastable levels to the low energies tungsten plasmas. [13] As for W 9+ and W 10+ , recently, Priti et al measured and analyzed the visible lines for W 8+ and W 9+ ions, [14] and Lu et al presented the visible lines from W 10+ . [15] But contribution from the metastable states to the total cross sections for W 9+ and W 10+ remain unclear.…”