Accurate Coulomb-fitting basis sets for H to Rn

TLDR

These auxiliary bases are slightly more than three times larger than orbital bases of split‑valence quality. The authors present a series of auxiliary basis sets for fitting Coulomb potentials for elements H to Rn, excluding lanthanides. For each element, a single auxiliary basis set approximates Coulomb energies when combined with split‑valence, triple‑zeta, or quadruple‑zeta orbital basis sets, yielding errors typically below ca. The sets achieve errors below ca.

Abstract

A series of auxiliary basis sets to fit Coulomb potentials for the elements H to Rn (except lanthanides) is presented. For each element only one auxiliary basis set is needed to approximate Coulomb energies in conjunction with orbital basis sets of split valence, triple zeta valence and quadruple zeta valence quality with errors of typically below ca. 0.15 kJ mol(-1) per atom; this was demonstrated in conjunction with the recently developed orbital basis sets of types def2-SV(P), def2-TZVP and def2-QZVPP for a large set of small molecules representing (nearly) each element in all of its common oxidation states. These auxiliary bases are slightly more than three times larger than orbital bases of split valence quality. Compared to non-approximated treatments, computation times for the Coulomb part are reduced by a factor of ca. 8 for def2-SV(P) orbital bases, ca. 25 for def2-TZVP and ca. 100 for def2-QZVPP orbital bases.