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 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.

Ab initio calculations of the hyperfine structure of Ra+ and evaluations of the electric quadrupole moment Q of the 209,211,221,223Ra nuclei

“…CCSD corresponds to the self-consistently iteration calculation. To investigate the ability of many-body methods to consider correlation effects under different theoretical frameworks, the lower-order many-body perturbation (MBPT) calculations [33,36] are also performed for comparison.…”

“…Then we find η 7p 3/2 = 0.051 KHz, ζ 7p 3/2 = 7.09 KHz, and ΔC 7p 3/2 = √ 5ζ 7p 3/2 2000 = 7.93 Hz. (36) For the ζ 7p 3/2 parameter, the contribution from off-diagonal matrix elements between 7p 3/2 and 7p 1/2 states with the lowest denominator of the energy difference is predominant, and the rest can be ignored.…”

Relativistic coupled-cluster calculation of hyperfine-structure constants of $^{229}$Th$^{3+}$ and evaluation of the electromagnetic nuclear moments of $^{229}$Th

“…( 4), one would obtain the transition matrix element within the CCSD or LCCSD approximation, respectively. The specific calculation steps are described in detail in our previous work [18,21].…”

“…In the present work, we employed a finite basis set composed of even-tempered Gaussian-type functions expressed as G i = N i r ℓ+1 e −ηir 2 , to expand the Dirac radial wave function P and Q as in Ref. [18,21,22], where N i is the normalization factor, and In our calculations, the no-pair Dirac Hamiltonian is set as the starting point. Breit interaction and the lowerorder quantum electrodynamics (QED) radiative potential proposed by Flambaum and Ginges [23] are considered at the same foot as coulomb interaction.…”