Detailed electron-impact excitation cross-section results for xenon in the wide range of incident energy from threshold to 1000 eV are calculated using relativistic distorted wave theory. Various transitions from the ground 5p 6 state to the excited 5p 5 6s, 5p 5 6p, 5p 5 5d, 5p 5 7s and 5p 5 7p as well as among these excited states are considered. The relativistic Dirac-Fock multi-configuration wave functions for the ground and excited states of Xe are obtained and used in the calculations. Where available, our cross-section results are compared with previously reported measurements and calculations. We have also fitted the calculated cross-sections through analytical formulae for plasma modeling purposes. As an application, using the obtained cross-sections, a collisional-radiative (C-R) model coupled with an optical emission measurement from the inductively coupled Xe plasma is developed and the extracted plasma parameters are reported.

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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.

Hyperfine structures of highly charged ions (HCIs) are favourable spectroscopic targets for exploring fundamental physics along with nuclear properties. Recent proposals of HCI atomic clocks highlight their importance, especially for many-electron HCIs, and they have been theoretically investigated by refining atomic-structure calculations. However, developments in hyperfine spectroscopy of many-electron HCIs have not proceeded due to experimental difficulty. Here, we demonstrate hyperfine-structure-resolved laser spectroscopy of HCIs in an electron beam ion trap plasma, employing the magnetic-dipole transition in the 4d95s state of 127I7+. Ion-state manipulation by controlled electron collisions in the well-defined laboratory plasma enables laser-induced fluorescence spectroscopy of trapped HCIs. The observed spectrum of evaporatively cooled ions under low magnetic fields shows characteristic features reflecting the hyperfine structures. The present demonstration using combined optical and plasma approaches provides a benchmark for state-of-the-art atomic calculations of hyperfine structures in many-electron HCIs, and offers possibilities for a variety of unexploited experiments.