Determination of the Energy Splitting between 3p3 2d5/2 And 2d3/2 States In Phosphorus-Like Ions

Abstract

The spectroscopic investigations on 3p3 2D5/2-2D3/2 transitions of phosphorus-like Ge17+, As18+, Se19+, Br20+, and Kr21+ ions at an electron beam ion trap were presented. The direct wavelength measurements were reported for the first time for Ge17+-Br20+ ions. All the measurements reached precision levels of a few ppm. The theoretical calculations were carried out using multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction methods including a large set of configuration state functions, in which the Breit interaction and QED effects were taken into account. The present results showed a good agreement between the theory and the experiment, and the divisions were less than 0.6%. Especially for the Kr21+ ions, meticulous scrutiny of line strengths with charge state distributions and continuity of results with isoelectronic sequence were performed to identify the measured spectral line as 3p3 2D5/2-2D3/2 transition. The present work resolved the long-standing confusion of the Kr21+ spectral line. Our accurate experimental results could be reference data for further calculations.

Keywords: Spectroscopy. Phosphorus-like ions. EBIT. MCDHF. RCI.