Description

This method keyword requests a Hartree-Fock calculation [ Roothaan51 C. C. J. Roothaan, “New Developments in Molecular Orbital Theory,” Rev. Mod. Phys., 23 (1951) 69. DOI: RevModPhys.23.69 ]. Unless explicitly specified, RHF is used for singlets and UHF for higher multiplicities. In the latter case, separate α and β orbitals will be computed [Berthier54, Pople54 J. A. Pople and R. K. Nesbet, “Self-Consistent Orbitals for Radicals,” J. Chem. Phys., 22 (1954) 571-72. DOI: 1.1740120 ] ([ McWeeny68 R. McWeeny and G. Dierksen, “Self-consistent perturbation theory. 2. Extension to open shells,” J. Chem. Phys., 49 (1968) 4852. DOI: 1.1669970 ] for electron correlation methods starting from a UHF reference). RHF, ROHF or UHF can also be specified explicitly.

適用範囲

Availability

Energies, analytic gradients, and analytic frequencies for RHF and UHF and numerical frequencies for ROHF.

実例

Examples

The Hartree-Fock energy appears in the output as follows:

      SCF Done:  E(RHF) =  -74.9646569691     A.U. after    4 cycles
      Conv  =     0.48D-08          -V/T =  2.0038

For UHF jobs, the output also prints S2 and related values:

 SCF Done:  E(UHF) =  -38.7068863059     A.U. after   11 cycles
             Convg  =    0.7647D-08             -V/T =  2.0031
 <Sx>= 0.0000 <Sy>= 0.0000 <Sz>= 1.0000 <S**2>= 2.0142 S= 1.0047
 <L.S>= 0.000000000000E+00
 Annihilation of the first spin contaminant:
 S**2 before annihilation     2.0142,   after     2.0001

The second and third lines give the SCF convergence limit and the expectation value of S2.