Segmented Contracted Error-Consistent Basis Sets of Double- and Triple‑ζ Valence Quality for One- and Two-Component Relativistic All-Electron Calculations

Segmented contracted
Gaussian basis sets optimized at the one-electron
exact two-component (X2C) level – including a finite size model
for the nucleus – are presented for elements up to Rn. These
basis sets are counterparts for relativistic all-electron calculations
to the Karlsruhe “def2” basis sets for nonrelativistic
(H–Kr) or effective core potential based (Rb–Rn) treatments.
For maximum consistency, the bases presented here were obtained from
the latter by modification and reoptimization. Additionally we present
extensions for self-consistent two-component calculations, required
for the splitting of inner shells by spin–orbit coupling, and
auxiliary basis sets for fitting the Coulomb part of the Fock matrix.
Emphasis was put both on the accuracy of energies of atomic orbitals
and on the accuracy of molecular properties. A large set of more than
300 molecules representing (nearly) all elements in their common oxidation
states was used to assess the quality of the bases all across the
periodic table.