A refined version of the ‘‘shape consistent’’ effective potential procedure of Christiansen, Lee, and Pitzer was used to compute averaged relativistic effective potentials (AREP) and spin–orbit operators for the elements Rb through Xe. Particular attention was given to the partitioning of the core and valence space and, where appropriate, more than one set of potentials is provided. These are tabulated in analytic form. Gaussian basis sets with contraction coefficients for the lowest energy state of each atom are given. The reliability of the transition metal AREPs was examined by comparing computed atomic excitation energies with accurate all-electron relativistic values. The spin–orbit operators were tested in calculations on selected atoms.

A b initio averaged relativistic effective core potentials (AREP) and spin–orbit (SO) operators are reported for the elements Cs through Rn. Two sets have been calculated for certain elements to provide AREPs with varying core/valence space definitions thereby permitting the treatment of core–valence correlation interactions. The AREPs and SO operators are tabulated as expansions in Gaussian-type functions (GTF). GTF valence basis sets for the lowest energy state of each atom are tabulated. The reliability of the AREPs and SO operators is gauged by comparing calculated atomic excitation energies and SO splitting energies with all-electron relativistic values. Calculated atomic excitation energies are found to agree to 0.12 eV and SO energies to 3.4%.

Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and