Slater-type basis sets
ADF uses Slater-Type Orbitals (STO's) as basis functions.
f(r) = Ylmrne-ζr
The center of the function is at a nucleus, the Ylm are spherical harmonics, and the exponential factor ζ (zeta) determines the long-range decay of the function. These STOs resemble the true atomic orbitals more closely than the more common Gaussian-Type Orbitals (GTO's). Therefore, fewer STO's than GTO's are needed for a given level of accuracy.
ADF has a database, which is included in the distribution, with thoroughly tested basis set files, ranging in quality from single-zeta to quadruple-zeta basis sets with various diffuse and polarization functions. All-electron and frozen-core basis sets are available for all elements, including lanthanides and actinides. The frozen-core approximation can be used to considerably reduce the computation time for systems with heavy nuclei, in a controlled manner. In the BAND program numerical orbitals are used in addition to STO's.
- STO's display the correct nuclear cusp and asymptotic decay
- basis sets for all elements (Z = 1 to 118)
- all electron, frozen-core
- SZ, DZ, DZP, TZP, TZ2P, QZ4P, even-tempered, diffuse
- non-relativistic and ZORA relativistically optimized
Links
Available standard basis sets for all elements (Z = 1 to 118)
ADF User Documentation: basis sets for ADF and BAND,
basis functions and orbitals
ADF-GUI: accuracy and efficiency
Related: ZORA STO basis sets that can be downloaded freely,
frozen-core approximation,
ZORA
