  We study the iron dimer by using an accurate ansatz for quantum chemical
calculations based on a simple variational wave function, defined by a single
geminal expanded in molecular orbitals and combined with a real space
correlation factor. By means of this approach we predict that, contrary to
previous expectations, the neutral ground state is $^7 \Delta$ while the ground
state of the anion is $^8 \Sigma_g^-$, hence explaining in a simple way a long
standing controversy in the interpretation of the experiments. Moreover, we
characterize consistently the states seen in the photoemission spectroscopy by
Leopold \emph{et al.}. It is shown that the non-dynamical correlations included
in the geminal expansion are relevant to correctly reproduce the energy
ordering of the low-lying spin states.
