Accurate universal gaussian basis set for helium through calcium generated with the generator coordinate Dirac-Fock method

Abstract

The recently developed generator coordinate Dirac-Fock method for closed-shell atoms is applied to generate an accurate universal gaussian basis set for the atoms from He ( Z = 2) through Ca ( Z = 20). The Dirac-Fock-Coulomb and Dirac-Fock-Breit energy results obtained with our universal gaussian basis set are compared with previous universal gaussian basis set Dirac-Fock-Coulomb and Dirac-Fock-Breit results, and with corresponding results obtained by numerical-finite-difference calculations. In general, our Dirac-Fock-Coulomb energies are better than the corresponding Dirac-Fock-Coulomb energies attained with the previous universal gaussian basis set, and are in excellent agreement with those obtained by the numerical-finite-difference method. For He and Be atoms, the Dirac-Fock-Coulomb energies obtained with our universal gaussian basis set are lower than the corresponding Dirac-Fock-Coulomb energies obtained by both numerical-finite-difference calculations and a previous universal gaussian basis set.