# CFOUR_REFERENCE

> Specifies the type of SCF calculation to be performed. RHF (= 0) requests a restricted Hartree-Fock reference; UHF (= 1) an unrestricted Hartree-Fock reference; ROHF (= 2) a restricted open-shell Hartree-Fock calculation; TCSCF (=3) a two-configurational SCF calculation, and CASSCF (=4) a complete-active space SCF calculations (currently not implemented). PSI4 Interface: Keyword subject to translation from value of REFERENCE unless set explicitly.

> - Type: string
> - Possible Values: RHF, UHF, ROHF, TCSCF, CASSCF
> - Default: RHF