Relativistic coupled-cluster calculation of hyperfine-structure constants of La 2+

Abstract Using the singles and doubles approximated relativistic coupled-cluster method, we calculate hyperfine-structure constant A and B of 24 low-lying states of La 2+ . The results of the lowest four states 5 d 3/2,5/2 and 4 f 5/2,7/2 are compared with recently measured values (Olmschenk et al 2017 Phys. Rev. A 96 032502). Reasonable agreement is found for hyperfine-structure constant A of 5 d 3/2 and 4 f 5/2,7/2 states, but the hyperfine-structure constant A of 5 d 5/2 and the hyperfine-structure constant B have a large deviation. To understand the role of the electron correlation effect, the intermediate results from lower-order many-body perturbation-theory and the linear version of coupled-cluster with single and double approximation are also presented. In the framework of coupled-cluster theory, the contribution trends from individual correlation effects are also investigated.