Slater-Type Basis Sets

The ADF program uses Slater-Type Orbitals. There are a number of basis sets that can be freely downloaded from this site.
These basis sets are optimized for the use in the zeroth-order regular approximated (ZORA) relativistic equation, which is an excellent approximation to the fully relativistic Dirac equation, especially in the valence region, which is important in quantum chemical calculations.

ZORA STO basis sets that can be downloaded freely

DZ fc: Double zeta frozen core
DZ ae: Double zeta all electron
TZP fc: Triple zeta frozen core 1 polarization function
TZP ae: Triple zeta all electron 1 polarization function
TZ2P fc: Triple zeta frozen core 2 polarization functions
TZ2P ae: Triple zeta all electron 2 polarization functions
QZ4P ae: Quadruple zeta all electron 4 polarization functions

E. van Lenthe and E.J. Baerends, Optimized Slater-type basis sets for the elements 1-118. Journal of Computational Chemistry 24, 1142 (2003)

Other basis sets

Especially for the lighter elements more STO basis sets are available in the data bases of the ADF program. One of the main developments in this respect are the even tempered basis sets developed by Del Chong.