Methods are selected by adding the appropriate keyword to the $CONTRL group, in the form: SCFTYP=keyword. Available methods are:
| Keyword | Description |
|---|---|
| RHF | Closed-shell, restricted Hartree-Fock wavefunctions |
| ROHF | Open-shell, restricted Hartree-Fock wavefunctions |
| UHF | Open-shell, unrestricted Hartree-Fock wavefunctions |
| GVB | Generalized valence bond wavefunction; needs input in $SCF group |
| MCSCF | Multiple configuration SCF wavefunctions; requires input in $DRT group |
If Moeller-Plesset perturbation theory treatment of electron correlation is desired, the keyword MPLEVEL=2 must be added. MP2 gradients are available only for RHF; single point MP2 is available for RHF, ROHF, UHF, and MCSCF.