Electric dipole polarizabilities of doubly ionized alkaline Earth metal ions from perturbed relativistic coupled-cluster theory

TL;DR

This paper calculates the electric dipole polarizabilities of doubly ionized alkaline earth metal ions using advanced relativistic coupled-cluster theory, including vacuum polarization effects, and finds results consistent with experimental data.

Contribution

It introduces a comprehensive relativistic coupled-cluster approach incorporating vacuum polarization corrections for accurate polarizability calculations.

Findings

Results agree well with experimental data.

Vacuum polarization effects vary across ions from Mg2+ to Ra2+.

Orbital energy corrections change nature with increasing atomic number.

Abstract

Using perturbed relativistic coupled-cluster (PRCC) theory we compute the ground state electric dipole polarizability, $\alpha$, of doubly ionized alkaline earth metal ions $\rm{Mg}^{2+}$, $\rm{Ca}^{2+}$, $\rm{Sr}^{2+}$, $\rm{Ba}^{2+}$ and $\rm{Ra}^{2+}$. In the present work we use the Dirac-Coulomb-Breit atomic Hamiltonian and we also include the Uehling potential, which is the leading order term in the vacuum polarization corrections. We examine the correction to the orbital energies arising from the Uehling potential in the self-consistent field calculations as well as perturbatively. Our results of $\alpha$ are in very good agreement with the experimental data, and we observe a change in the nature of the orbital energy corrections arising from the vacuum polarization as we go from $\rm{Mg}^{2+}$ to Ra$^{2+}$.