Dipole polarizabilities of the transition and post-transition metallic systems

TL;DR

This study examines how electron correlation effects influence the calculation of electric dipole polarizabilities in transition and post-transition metals using various relativistic many-body methods, achieving high accuracy with CCSD and CCSDpT.

Contribution

It provides a comprehensive comparison of multiple many-body methods for calculating polarizabilities, highlighting the importance of triple excitations for accuracy.

Findings

CCSD results agree within 1% of experimental data.

Including triple excitations improves the accuracy further.

Correlation effects vary among element groups but show similar trends among isoelectronic systems.

Abstract

We investigate the role of the electron correlation effects in the calculations of the electric dipole polarizabilities (\alpha) of elements belonging to three different groups of periodic table. To understand the propagation of the electron correlation effects at different levels of approximations, we employ the relativistic many-body methods developed, based on the first principles, at mean-field Dirac-Fock (DF), third order many-body perturbation theory (MBPT(3)), random-phase approximation (RPA) and the singly and doubly approximated coupled-cluster methods at the linearized (LCCSD) and non-linearized (CCSD) levels. We observe variance in the trends of the contributions from the correlation effects in a particular group of elements through a employed many-body method; however they resemble similar tendency among the isoelectronic systems. Our CCSD results are within sub-one percent agreement with the experimental values which are further ameliorated by including the contributions from the important triple excitations (CCSD$_p$T method).