Single Point: RHF / UHF / ROHF

RHF Single Point — Water, STO-3G

task: RHF STO-3G

MOLECULE
  Charge        0
  Multiplicity  1
  Units         Angstrom
END

GEOMETRY
  O   0.000000   0.000000   0.117369
  H   0.756950   0.000000  -0.469476
  H  -0.756950   0.000000  -0.469476
END

RHF Single Point — H₂, Coordinates in Bohr

task: RHF STO-3G

MOLECULE
  Units  Bohr
END

GEOMETRY
  H  0.0  0.0  0.0
  H  0.0  0.0  1.4
END

UHF Single Point — Hydroxyl Radical (Doublet)

task: UHF 6-31G*

MOLECULE
  Charge        0
  Multiplicity  2
END

GEOMETRY
  O   0.000000   0.000000   0.000000
  H   0.000000   0.000000   0.970000
END

ROHF Single Point — Oxygen Atom (Triplet)

task: ROHF STO-3G

MOLECULE
  Charge        0
  Multiplicity  3
END

GEOMETRY
  O  0.0  0.0  0.0
END

Notes

  • For UHF, set Multiplicity 2 in MOLECULE (doublet: 2S+1 = 2).
  • For ROHF, set Multiplicity 3 in MOLECULE (triplet: 2S+1 = 3).
  • The Algorithm in the SCF section is typically redundant with the task: line.