Ab initiostudies of electron correlation and Gaunt interaction effects in the boron isoelectronic sequence using coupled-cluster theory

Abstract

In this paper, we study electron correlation and Gaunt interaction effects in ionization potentials (IPs) and hyperfine constants A of $2p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{1/2}$ and $2p{\phantom{\rule{0.16em}{0ex}}}^{2}\phantom{\rule{-0.16em}{0ex}}{P}_{3/2}$ states along with fine structure splitting (FSS) between them for the boron isoelectronic sequence using the relativistic coupled-cluster method. The range of atomic number $z$ is taken from 8 to 21. The Gaunt contributions can be calculated at both the Dirac-Fock and the coupled-cluster levels from our presentation. Calculated IPs and FSS are compared with the results of the National Institute of Standards and Technology. Important correlation contributions like the core correlation, core polarization, and pair correlation effects are studied for hyperfine constants A. Many distinct features of the correlation and relativistic effects are observed in these studies.