Relativistic and electron-correlation contributions to the dipole polarizability of the alkaline-earth-metal atoms Ca, Sr, and Ba

A series of high-level correlated (many-body-perturbation-theory and coupled-cluster) calculations on the dipole polarizability of Ca, Sr, and Ba has been carried out. The relativistic effects have been incorporated in calculations at both the Hartree-Fock and correlated levels of approximation. Calculated values of the dipole polarizability of Ca, Sr, and Ba are 152, 190, and 273 a.u., respectively, and in agreement with experimental data from electric-deflection measurements. The relativistic effect on the dipole polarizability is very small (-2 a.u.) for Ca, amounts to about -11 a.u. for Sr, and becomes comparable with the electron-correlation contribution for Ba (-37 a.u.). An optimized Gaussian basis set has been generated for Ba, the details of which are included in the paper.