Prominent enhancement on the radiative branching ratio of the doubly excited resonant states due to the Breit interaction induced ion-core energy inversion. (May 2020)

• Record Type: Journal Article
• Authors: Wu, Chensheng; Xie, Lu-You; Hu, Zhimin; Gao, Xiang
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 246(2020)
• Publication Date: 2020-05
• Subjects: Highly charged ions -- Electric dipole radiative transition Relativistic effect; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2020.106912
• Languages: English
• ISSNs: 0022-4073

Abstract

Highlights: A new mechanism that the Breit interaction effects significantly in the highly charged Li- and B-like ions are studied, the strongly correlated many-body wavefunctions of the doubly excited resonant states [1s2p1/2 2p3/2 ]3/2 (or [1s(2s 2 )2p1/2 2p3/2 ]3/2 ) 4 P3/2 and 2 D3/2 are drastically influenced by the Breit interaction. The strong variation of wavefunctions results in a prominent change of the two dominant transitions 2p3/2 –1 s and 2p1/2 –1 s of the doubly excited states. The variation of the transitions can be observed in experiment by measuring the branching ratio of the doubly excited Li-like or B-like ions. The variation of the wavefunctions is due to the ion-core energy inversion induced by the Breit interaction. Based on the mechanism, we propose an alternative experimental determination of the fine structure splitting of [1s2p1/2 ]0, 1 (or [1s(2s 2 )2p1/2 ]0, 1 ) in heavy He-like (or Be-like) ions from the branching ratio of the doubly excited Li-like (or B-like) ions. This work extends the conventional wisdom on the role of the relativistic effects in the electric dipole radiative transitions of highly charged ions, which could be useful for future precise high-temperature plasma diagnostics. Abstract: The Breit interaction is the relativistic correction to the electron-electron interaction which mainly affects the level energies, and it is minor in general. We present a new manifestation of the Breit interaction effects in the highly charged Li- and B-like ions based on the multi-configuration Dirac-Fock calculations, where the strongly correlated many-body wavefunctions of the doubly excited resonant states [1s2p1/2 2p3/2 ]3/2 (or [1s(2s 2 )2p1/2 2p3/2 ]3/2 ) 4 P3/2 and 2 D3/2 are drastically influenced by the Breit interaction. The strong variation of wavefunctions results in a prominent enhancement of the radiative branching ratio between the two dominant transitions 2p3/2 -1s and 2p1/2 -1s of the doubly excited states. We elucidate the intrinsic mechanism of this effect is due to the ion-core energy inversion induced by the Breit interaction, and suggest that the possible experimental measurements can be achieved via the dielectronic recombination processes in an electron beam ion trap facility. Based on this effect, we also propose an alternative experimental determination of the fine structure splitting of [1s2p1/2 ]0, 1 (or [1s(2s 2 )2p1/2 ]0, 1 ) in heavy He-like (or Be-like) ions from the branching ratio of the doubly excited Li-like (or B-like) ions, which is sensitive to the fine structure level inversions and can be served as a complementary tool to the available hyperfine quenching experimental method aiming for the absolute value of the splitting.