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FSGO HARTREE-FOCK INSTABILITIES OF HYDROGEN 195
In the Extended Hartree-Fock (EHF) technique, the minimization is performed on the
form of the PHF wave function. This type of wave function should produce for each
interatomic distance a further lowering of the energy with respect to the RHF, UHF, and
PHF total energies. The values of E(PHF-FSGO), and E(EHF-FSGO) for internuclear
distances from 1.0 a.u. to 7 a.u. (step 0.5 a.u.) are also given in Table 2. As in the UHF
case, we have the "correct" dissociation behavior
Indeed, the extrapolated values converge to the expected values; we have shown that in
the RHF symmetric case, the limiting situation is an asymptotic energy
-
which should correspond to the H described whose two electrons are described by a
single Gaussian:
With the optimisation condition:
