We present the extension of the system of error-consistent segmented contracted Gaussian basis sets (Karlsruhe def2-bases Weigend and Ahlrichs, Phys. Chem. Chem. Phys., 2005, 7, 3297–3305) for the lanthanide large core effective core potentials (lcECPs) designed by Dolg, Stoll, Savin and Preuss, Theor. Chim. Acta, 1989, 75, 173–194. For La–Lu, sets of double zeta (“split”, S), triple zeta (TZ), and quadruple zeta (QZ) valence (V) quality were optimized in atomic Hartree–Fock calculations for each of the different lcECPs that model the occupations fn−k, k = 0, 1, 2, and n being the (typical) ground state f shell occupation; e.g. for Pr, n = 3, for each of the occupations f3, f2, and f1, an SV, TZV, and QZV basis were optimized and termed lcecp-k-XV (k = 0, 1, 2, X = S, TZ, QZ). Polarization functions for the quadruple zeta valence bases were taken from Weigand, Cao, Yang, and Dolg, Theor. Chem. Acc., 2010, 126, 117–127, for the smaller basis sets they were appropriately reduced. The conformity with the def2-series in regards to error-consistency was assessed for a set of 120 molecules by comparing distances, bond angles, vibration frequencies and exchange reaction energies in regards to the basis set limit and also to all-electron scalar relativistic calculations.
Lukanowski et al. (Thu,) studied this question.