Theoretical calculation on energy levels of 1s²2p state for highly charged Li-like isoelectronic sequence (Z = 31 ∼ 40)

The fine structures of 1s²2p state in the highly charged Li-like isoelectronic sequence ions (Z = 31 ∼ 40) are investigated using the multi-configuration Dirac-Fock method. With inclusion of the correlation effect from the high correlation orbital as well as the high-order correction from the Breit interaction, quantum electrodynamics and nuclear motion effects, the energies of fine structure levels ²P_1/2 and ²P_3/2 are calculated, and the energy splitting obtained agrees well with the theoretical data available. The results show that the fine structure splitting of 1s²2p state in Li-like ions satisfies the scaling law ( ∼ Z⁴) of highly charged isoelectric sequence. As the atomic number increases, the distribution of the radial electronic density approaches to the nucleus for the relativistic orbitals 1s_1/2 and 2p_3/2, indicating the smaller radius of the Li-like ion. (authors)