title: Automatic Generation of Auxiliary Basis Sets.
abstract: A procedure was developed to automatically generate auxiliary basis sets (ABSs) for use with the resolution of the identity (RI) approximation, starting from a given orbital basis set (OBS). The goal is to provide an accurate and universal solution for cases where no optimized ABSs are available. In this context, "universal" is understood as the ability of the ABS to be used for Coulomb, exchange, and correlation energy fitting. The generation scheme (denoted AutoAux) works by spanning the product space of the OBS using an even-tempered expansion for each atom in the system. The performance of AutoAux in conjunction with different OBSs [def2-SVP, def2-TZVP, def2-QZVPP, and cc-pwCVnZ (n = D, T, Q, 5)] has been evaluated for elements from H to Rn and compared to existing predefined ABSs. Due to the requirements of simplicity and universality, the generated ABSs are larger than the optimized ones but lead to similar errors in MP2 total energies (on the order of 10-5to 10-4Eh/atom).
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Mülheim an der Ruhr 45470, Germany.
authors.forename: Georgi L
authors.identifier: http://orcid.org/0000-0002-3408-5749
authors.initials: GL
authors.lastname: Stoychev
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Mülheim an der Ruhr 45470, Germany.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Auer
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Mülheim an der Ruhr 45470, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Neese