Atomic data for six-times ionized krypton (Kr VII): energy levels, allowed and forbidden transitions

Accurate atomic data for ionized noble gases are essential in various scientific and industrial fields, including astrophysics, plasma diagnostics, and fusion research. In this study, we investigate the atomic structure and radiative transition parameters of six-times ionized krypton (Kr VII), a Zn-like ion of astrophysical and technological importance. The energy levels of Kr VII were calculated using the fully relativistic multi-configuration Dirac–Fock (MCDF) method implemented in the GRASP code. The effects of quantum electrodynamics (QED) corrections and Breit interactions were also taken into account in the MCDF calculations to improve the accuracy of the computed energy levels. In addition, electric dipole (E1), electric quadrupole (E2), and magnetic dipole (M1) transition parameter including wavelengths (λ), transition probabilities (A_ij), oscillator strengths (f_ji), and line strengths (S_ij) were systematically evaluated. The results were compared with available experimental and theoretical data in the literature. While existing studies provide partial data for some levels and E1 transitions, our work presents new results, especially for E2 and M1 transitions, which have not been previously reported. This study not only enhances the atomic dataset for Kr VII but also contributes original spectroscopic parameters to the current literature, supporting future astrophysical modeling and plasma diagnostics.

Graphical abstract