Medium-size polarized basis sets for high-level-correlated calculations of molecular electric properties: III. Alkali (Li, Na, K, Rb) and alkaline-earth (Be, Mg, Ca, Sr) atoms

Abstract

The basis set polarization method is applied for the generation of medium size polarized basis sets for Li, Na, K, Rb, Be, Mg, Ca, and Sr. The derived basis sets are shown to give satisfactory results in calculations of atomic dipole polarizabilities and in calculations of dipole moments and dipole polarizabilities of diatomic hydrides and hydride ions at both the SCF and highly correlated levels of approximation. The MBPT and CC results for hydrides and hydride ions of the group Ia and IIa metals calculated with polarized basis sets derived in this study indicate the importance of the electron correlation contribution to the electric properties of those systems. The dominant part of this contribution involves excitations from core orbitais of the metal atom and is recognized as the core polarization effect. The valence approximation is found to be completely unsatisfactory for hydrides involving heavier metals of the present series. Details of the basis set data supplement this paper. Some possible applications of those basis sets are surveyed.