Optimization of auxiliary basis sets for RI-MP2 and RI-CC2 calculations: Core–valence and quintuple-ζbasis sets for H to Ar and QZVPP basis sets for Li to KrThe optimized auxiliary basis sets reported in the present work are available together with those of refs. 1 and 16by ftp27or on request from the author. The implemented analytic basis set gradient for the functional δRIis available as part of the TURBOMOLE program package. For details the reader is refered to the TURBOMOLE web page.25

An implementation of analytic basis set gradients is reported for the optimization of auxiliary basis sets in resolution-of-the-identity second-order Møller–Plesset perturbation theory RI-MP2 and approximate coupled-cluster singles-and-doubles RI-CC2 calculations. The analytic basis set gradients are applied in the optimization of auxiliary basis sets for a number of large one-electron orbital basis sets which provide correlation energies close to the basis set limit: the core–valence basis sets cc-pwCVXZ B–Ne, Al–Ar with X D, T, Q, 5, the quintuple-ζbasis sets cc-pV5Z H–Ar and cc-pV5 dZ Al–Ar and the doubly-polarized valence quadruple-ζbasis sets QZVPP for Li–Kr. The quality of the optimized auxiliary basis sets is evaluated for several test sets with small and medium sized molecules.