Excitation Energies and Fine Structure Splittings for 1s²nd (n≤9) States of Ni²⁵⁺ Ion

Abstract

The excitation energies and fine structure splittings of 1s 2 nd (n  9) states for Ni 25+ ion are calculated in this paper. Non-relativistic energies are obtained with the eigenvalue of non-relativistic Hamiltonian operators; the relativistic and mass-polarization effects on the energies are included as the first-order perturbation. The fine structure splittings are determined from the expectation value of spin-orbit and spin-other orbit interaction operators. In order to make the results more precise, quantum-electrodynamics (QED) contribution and higher-order relativistic contribution are considered for highly charged Ni 25+ ion. The results of fine structure splittings agree with the experimental data excellently, and the error is no more than several cm −1. Compared the excitation energy calculated with experimental data, the relative error is only 0.2‰-0.6‰. It indicates the results obtained in this paper are both reliable and accurate.