Correlation trends in the ground state static electric dipole polarizabilities of closed-shell atoms and ions

TL;DR

This paper uses advanced relativistic coupled-cluster theory to accurately calculate ground state electric dipole polarizabilities of atoms and ions, emphasizing the importance of higher order correlation effects for improved precision.

Contribution

It introduces a method to incorporate higher order many-body effects into RCC calculations and compares these results with perturbation theory to highlight their significance.

Findings

Higher order correlation effects significantly improve polarizability accuracy.

The developed method effectively constructs intermediate diagrams for coupled-cluster amplitudes.

Comparison shows RCC results outperform lower-order perturbation theory.

Abstract

We employ the closed-shell perturbed relativistic coupled-cluster (RCC) theory developed by us earlier [Phys. Rev. A {\bf 77}, 062516 (2008)] to evaluate the ground state static electric dipole polarizabilities (\alpha s) of several atomic systems. In this work, we have incorporated a class of higher order many-body effects in our calculations that had not been taken into account in the above paper. We highlight their importance in improving the accuracy of $\alpha$. We also calculate the ground state \alpha s of the inert gas atoms and several iso-electronic singly and doubly charged ions in order to make a comparative study of the trends of the correlation effects. Furthermore, we have developed a method to construct intermediate diagrams that are required for the computation of the unperturbed singles and doubles coupled-cluster amplitudes. Our RCC results are compared with those of many-body perturbation theory at different orders to demonstrate the importance of higher order correlation effects for the accurate determination of (\alpha s) of the systems that we have considered.