Even tempered basis sets for four-component relativistic quantum chemistry

A series of even tempered basis sets for four-component relativistic quantum chemical calculations are presented. The sets have been derived within the dual family scheme, reducing the number of independent parameters to a minimum. The sets are based on optimization of the atomic energies in Dirac-Hartree-Fock calculations. It is also shown that within the dual family scheme the derivation of higher angular momentum polarization functions for correlated calculations becomes rather simple, and such sets based on four-component MP2 calculations are presented for closed shell atoms. The performance of these even tempered sets is compared with that of other basis sets from different schemes in calculations on LaCl and LuCl. (C) 2004 Elsevier B.V. All rights reserved.