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Extreme ultraviolet spectra and analysis of ¿n=0 transitions in highly charged barium



Joseph Reader, John D. Gillaspy, Dmitry D. Osin, Yuri Ralchenko


Extreme ultraviolet spectra of highly charged barium atoms were produced with an electron beam ion trap (EBIT) and recorded with a flat-field grazing-incidence spectrometer. The spectra were measured in the wavelength range 4 nm to 24 nm with the beam energies varying from 700 eV to 30000 eV. The line identifications were performed with collisional-radiative modeling of the EBIT plasma that provided good quantitative agreement between simulated and measured spectra. In the energy range 700 eV to 1750 eV, fifty three n=4-n=4 transitions in Se-like (Ba22+) to Cu-like (Ba27+ ) ions were identified, with forty seven corresponding to new lines. Almost all lines are due to electric-dipole transitions. For the beam energies of 3945 eV to 7530 eV, we identified eight new n=3-n=3 transitions in Ba42+ (Si-like), Ba43+ (Al-like), and Ba44+ (Mg-like). At the highest beam energy, 30000 eV, three new n=2-n=2 transitions of Ba51+ (B-like), Ba52+ (Be-like), and Ba53+ (Li-like) were identified. The measured wavelengths are compared with recent ab initio theoretical calculations. An improved ionization energy for Ba26+ (Zn-like), IE = (937.5±0.8) eV, was determined by comparing theoretical values with measurements along the Zn isoelectronic sequence.
Journal of Physics B-Atomic Molecular and Optical Physics


barium, spectra, extreme ultraviolet, ionization potential, electron beam ion trap


Reader, J. , Gillaspy, J. , Osin, D. and Ralchenko, Y. (2014), Extreme ultraviolet spectra and analysis of ¿n=0 transitions in highly charged barium, Journal of Physics B-Atomic Molecular and Optical Physics, [online], (Accessed August 3, 2021)
Created July 4, 2014, Updated February 19, 2017