Employing the homotopy method we have obtained the complete set of real solutions to the equations of the restricted Hartree-Fock method as well as the full set of solutions to the equations of the coupled-cluster-with-doubles method for the H4 and P4 models broadly applied in various many-electron studies. These are the first global results obtained so far for any formulations of the Hartree-Fock and coupled-cluster methods when applied to realistic models.

• Received 19 March 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.1195