The Landé g factors for the 6S_1/2, 5D_3/2,5/2 states of Ba⁺ ions

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 ²S_1/2 and 5d 2D_3/2,5/2 states of Ba⁺ ions were calculated using the multi-configuration Dirac-Hartree-Fock (MCDHF) method and the Model-QED method. The contributions of the electron correlation effects and quantum electrodynamics (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.