Relativistic and electron-correlation effects in static dipole polarizabilities for group 12 elements

In this study, we report a comprehensive calculation of the static dipole polarizabilities of group 12 elements using the finite-field approach combined with the relativistic coupled-cluster method, including single, double, and perturbative triple excitations. Relativistic effects are systematically investigated, including scalar-relativistic, spin-orbit coupling (SOC), and fully relativistic Dirac-Coulomb contributions. The final recommended polarizability values are 37.95 ± 0.77 a.u. for Zn, 45.68 ± 1.21 a.u. for Cd, 34.04 ± 0.68 a.u. for Hg, and 27.92 ± 0.28 a.u. for Cn. These results are in excellent agreement with the 2018 Table of static dipole polarizabilities for neutral atoms [P. Schwerdtfeger and J. K. Nagle, Mol. Phys., 2019, 117, 1200] and provide reduced uncertainties for Cd and Cn. Our analysis shows that scalar-relativistic effects dominate the relativistic corrections, with SOC contributions found to be negligible. The role of electron correlation is thoroughly examined across the non-relativistic, scalar-relativistic, and fully relativistic Dirac-Coulomb regimes, underscoring its critical importance in achieving accurate polarizability predictions.