Recent progress in atomic and chemical group effective potentials

Recent progress on atomic and chemical group effective potentials is presen ted. The reviewed effective potentials follow a shape-consistent extraction technique from ab initio data, within a scalar relativistic approximation. Two types of averaged relativistic effective core potentials are considere d: the correlated ones where a part of the correlation energy is included i n the effective potential, and the polarized ones for which only the core p olarization effects are taken into account. In addition spin-orbit polarize d pseudopotentials have been extracted, and the effects of the core polariz ation are tested on the atomic spectroscopy of iodine. Finally a very recen t chemical group effective methodology is presented, reducing the number of both electrons and nuclei explicitly treated. Chemical transferability is investigated, and test calculations on a cyclopentadienyl effective group p otential are presented.