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A series of correlation consistent basis sets have been developed for the post-d group 16-18 elements in conjunction with small-core relativistic pseudopotentials of the energy-consistent variety. The latter were adjusted to multiconfiguration Dirac-Hartree-Fock data based on the Dirac-Coulomb-Breit Hamiltonian. The outer-core (nϪ1)spd shells are explicitly treated together with the nsp valence shell with these PPs. The accompanying cc-pVnZ-PP and aug-cc-pVnZ-PP basis sets range in size from DZ to 5Z quality and yield systematic convergence of both Hartree-Fock and correlated total energies. In addition to the calculation of atomic electron affinities and dipole polarizabilities of the rare gas atoms, numerous molecular benchmark calculations ͑HBr, HI, HAt, Br 2 , I 2 , At 2 , SiSe, SiTe, SiPo, KrH ϩ , XeH ϩ , and RnH ϩ) are also reported at the coupled cluster level of theory. For the purposes of comparison, all-electron calculations using the Douglas-Kroll-Hess Hamiltonian have also been carried out for the halogen-containing molecules using basis sets of 5Z quality.

Nonrelativistic and quasirelativistic ab-initio pseudopotentials representing the Ne-like X(Z−10)+ cores (X=Sc–Zn) of the first row transition metals and optimized (8s7p6d1f )/[6s5p3d1f ]-GTO valence basis sets for use in molecular calculations have been generated. Excitation and ionization energies of the low lying states of Sc through Zn from numerical HF- as well as SCF- and CI(SD)-pseudopotential calculations using the derived basis sets differ by less than 0.1 eV from corresponding all-electron results.