Pseudopotentials and modelpotentials

The basic assumptions of quantum chemical ab initio valence-only (VO) schemes, i.e., pseudopotential and modelpotential approaches, are briefly discussed. Both effective core potential schemes lead to a reduction of the computational effort for wavefunction-based as well as density functional theory electronic structure calculations in comparison to corresponding all-electron treatments and allow to include the most important relativistic contributions implicitly into formally nonrelativistic calculations by means of a suitable parameterization of the VO model Hamiltonian. (C) 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 200-210 DOI: 10.1002/wcms.28