KCS

Electric static dipole polarizabilities and ionization potentials of the first and second main group elements are obtained through ab-initio and pseudopotential methods of relativistic quantum chemistry. Demonstrated is the high accuracy achieved in the predicted properties through a development of correlation consistent basis sets and scalar and two-component small-core pseudopotentials. Electron correlation effects are discussed at the coupled-cluster level of theory and relativistic effects using spin-free Douglas-Kroll Hamiltonian and four-component Dirac-Coulomb-Hartree-Fock scheme to account for spin-orbit coupling effects followed by a second-order many-body perturbation treatment for electron correlation. Also presented is an application of the pseudopotentials to molecular species, namely the alkali dimers and their singly charged ions. Selected spectroscopic properties and dipole polarizabilities of these dimers are discussed.