The study of atomic structure parameters for n = 4 - n = 3 transitions in Mg-like ions with 15≤Z≤30

Abstract

Multiconfiguration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction (RCI) methods are utilized for theoretical calculations of energy levels, wavelengths, line strengths, absorption oscillator strengths, and transition probabilities in 3s²-3s4p, 3s3p-3s4s, 3s3p-3s4d, 3s3p-3p4p, 3s3d-3s4f, 3p²-3p4s, 3p²-3p4d, and 3p3d-3p4f transitions in Mg-like ions with $15\le Z\le 30$. The calculations of energies account for Breit interaction and quantum electrodynamics (QED) contributions. The active space approximation is employed for the calculations, and energy converges when the active orbital set is increased to $n$ = 7. The calculated lowest 78 levels including valence and core–valence correlations in Mg-like ions with Z=15–30 show good agreement with experiment results and other calculations. The relative difference between calculated wavelengths and experiment values exhibits a decreasing trend as the atomic numbers increase, and the difference is better than 1% for a majority of transitions. To evaluate the accuracy of the wave functions and transition parameters, the quantity $dT$ is analyzed within 0.1 for most strong transitions. The transition probabilities are compared with other theoretical values to analyze with line strength S. Such calculations may provide valuable data for the experimental study of plasma diagnostics and modeling as there are others.