  Within the framework of Fermionic Molecular Dynamics a method is developed to
better account for long range tensor correlations in nuclei when working with a
single Slater determinant. Single-particle states with mixed isospin and broken
parity build up an intrinsic Slater determinant which is then charge and parity
projected. By minimizing the energy of this many-body state with respect to the
parameters of the single-particle states and projecting afterwards on angular
momentum ground state energies are obtained that are systematically lower than
corresponding Hartree-Fock results. The realistic Argonne V18 potential is used
and short range correlations are treated with the Unitary Correlation Operator
Method. Comparison with exact few-body calculations shows that in $^4$He about
one fifth of the correlation energy due to long-range correlations are
accounted for. These correlations which extend over the whole nucleus are
visualized with the isospin and spin-isospin density of the intrinsic state.
The divergence of the spin-isospin density, the source for pion fields, turns
out to be of dipole nature.
