CamCASP/Programming/5

CamCASP => Programming => Auxiliary basis sets

Spherical versus Cartesian GTOs

• What are the advantages of the two basis types: Spherical and Cartesian?
• Which one results in more accurate energies and why?

Spherical GTOs:

1. Smaller in size
2. More well-defined set of linear equations during DF
3. Lower accuracy.
4. Seemingly erratic behaviour in aug-cc-pVnZ series.
5. Rotations made easy as we have the Wigner rotation matrices.

Cartesian GTOs:

1. Larger in size
2. DF equations seem OK.
3. Higher accuracy of energies
4. More consistent behaviour of aug-cc-pVnZ series.
5. Don't have rotation matrices coded, but these have been derived.