  To gain some insight into the structure and physical significance of the
multiple solutions to the coupled-cluster doubles (CCD) equations corresponding
to the Pariser-Parr-Pople (PPP) model of cyclic polyenes, complete solutions to
the CCD equations for the A^{-}_{1g} states of benzene are obtained by means of
the homotopy method. By varying the value of the resonance integral beta from
-5.0 eV to -0.5 eV, we cover the so-called weakly, moderately, and strongly
correlated regimes of the model. For each value of beta 230 CCD solutions are
obtained. It turned out, however, that only for a few solutions a
correspondence with some physical states can be established. It has also been
demonstrated that, unlike for the standard methods of solving CCD equations,
some of the multiple solutions to the CCD equations can be attained by means of
the iterative process based on Pulay's direct inversion in the iterative
subspace (DIIS) approach.
