HF

DESCRIPTION

This method keyword requests a Hartree-Fock calculation. Unless explicitly specified,RHFis used for singlets andUHFfor higher multiplicities. In the latter case, separate α and β orbitals will be computed[Roothaan51,Pople54,McWeeny68].RHF,ROHForUHFcan also be specified explicitly.

AVAILABILITY

Energies, analytic gradients, and analytic frequencies forRHFandUHFand numerical frequencies forROHF.

EXAMPLES

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

SCF Done: E(RHF) = -74.9646569691 A.U. after 4 cycles Convg = .6164D-03 -V/T = 2.0063

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

For UHF jobs, the output also prints S2and related values:

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

Last update: 23 April 2013

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