Electron-correlation and relativistic contributions to atomic dipole polarizabilities: Alkali-metal atoms.

Abstract

Electric-dipole polarizabilities of K, Rb, Cs, and Fr are calculated in the framework of the quasirelativistic method based on mass-velocity and Darwin terms in the Pauli Hamiltonian. The electron-correlation contribution due to atomic cores is taken into account at two levels of approximation. The next-to-valence-shell contributions follow from the appropriate complete active-space multiconfiguration self-consistent-field calculations while the remaining core correlation effects are evaluated by using a second-order-perturbation method. Both pure relativistic and mixed correlation-relativistic contributions are evaluated. The present nonrelativistic results for K (44.6 A${\mathrm{\r{}}}^{3}$), Rb (60.8 A${\mathrm{\r{}}}^{3}$), Cs (72.8 A${\mathrm{\r{}}}^{3}$), and Fr (81.8 A${\mathrm{\r{}}}^{3}$) are reduced by 0.8 A${\mathrm{\r{}}}^{3}$, 11.3 A${\mathrm{\r{}}}^{3}$, 11.5 A${\mathrm{\r{}}}^{3}$, and 33.5 A${\mathrm{\r{}}}^{3}$, respectively, due to relativistic and correlation-relativistic corrections. The quasirelativistic results for K, Rb, and Cs are in good agreement with experimental data. The predicted dipole polarizability of Fr is 48.3 A${\mathrm{\r{}}}^{3}$. Additionally, polarized basis sets for Cs and Fr for calculations of molecular electric properties have been generated in this study.