# Electric dipole polarizability of group-IIIA ions using PRCC: Large correlation effects from nonlinear terms

## TL;DR

This study calculates the electric dipole polarizability of group-IIIA ions using advanced relativistic coupled-cluster methods, highlighting the importance of nonlinear terms and various quantum electrodynamics corrections for accurate results.

## Contribution

The paper introduces the use of PRCC with nonlinear terms and QED corrections to accurately compute polarizabilities of group-IIIA ions, showing significant effects of nonlinear contributions.

## Key findings

- Nonlinear terms in PRCC significantly affect polarizability values.
- Breit interaction correction is largest for Al+ and decreases for heavier ions.
- Vacuum polarization and self-energy corrections increase with ion mass.

## Abstract

We compute the ground-state electric dipole polarizability of group-IIIA ions using the perturbed relativistic coupled-cluster (PRCC) theory. To account for the relativistic effects and QED corrections, we use the Dirac-Coulomb-Breit Hamiltonian with the corrections from the Uehling potential and the self-energy. The effects of triple excitations are considered perturbatively in the PRCC. Our PRCC results for $\alpha$ are good in agreement with the previous theoretical results for all the ions. From our computations we find that the nonlinear terms in PRCC have significant contributions and must be included to obtain the accurate value of $\alpha$ for group-IIIA ions. For the correction from the Breit interaction, we find that it is largest for Al$^+$ and decreases as we go towards the heavier ions. The corrections from the vacuum polarization and the self-energy increase from lighter to heavier ions.