The Landé <i>g</i> Factors for the 6S_1/2 and 5D_3/2,5/2 States of Ba⁺ Ions

Abstract The Landé g factors of Ba + are very important in high-precision measurement physics. The wave functions, energy levels, and Landé g factors for the 6s 2 S 1/2 and 5d 2 D 3/2,5/2 states of Ba + ions were calculated using the multi-configuration Dirac–Hartree–Fock method and the model-quantum electrodynamics (QED) method. The contributions of the electron correlation effects and QED effects were discussed in detail. The transition energies are in excellent agreement with the experimental results, with differences of approximately 5 cm −1 . The presently calculated g factor of 2.0024905(16) for the 6S 1/2 agrees very well with the available experimental and theoretical results, with a difference at a level of 10 −6 . For the 5D 3/2,5/2 states, the present results of 0.7993961(126) and 1.2003942(190) agree with the experimental results of 0.7993278(3) [ Phys. Rev. A 54 1199 (1996) ] and 1.20036739(14) [ Phys. Rev. Lett. 124 193001 (2020) ] very well, with differences at the level of 10 −5 .