Instability of closed-shell Hartree-Fock solutions within the framework of the geminal approach

The universal instability of the closed-shell Hartree-Fock solution within the framework of the approach in which the wave function is approximated by an antisymmetrized product of geminals was proved. It was shown that these results are applicable to the Goddard Gl-function method, the generalized valence bonds method, and also the Smeyers gamma-function method.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 4, pp. 394–400, July–August, 1986.