Relativistic coupled-cluster calculation of hyperfine-structure constants of La2+

Using the singles and doubles approximated relativistic coupled-cluster method, we calculate hyperfine-structure constant A and B of 24 low-lying states of La2+. The results of the lowest four states 5d(3/2,5/2) and 4f(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 5d(3/2) and 4f(5/2,7/2) states, but the hyperfine-structure constant A of 5d(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.