  We present detailed results of Unrestricted Hartree-Fock (UHF) calculations
for up to eight electrons in a parabolic quantum dot. The UHF energies are
shown to provide rather accurate estimates of the ground-state energy in the
entire range of parameters from high densities with shell model characteristics
to low densities with Wigner molecule features. To elucidate the significance
of breaking the rotational symmetry, we compare Restricted Hartree-Fock (RHF)
and UHF. While UHF symmetry breaking admits lower ground-state energies,
misconceptions in the interpretation of UHF densities are pointed out. An
analysis of the orbital energies shows that for very strong interaction the UHF
Hamiltonian is equivalent to a tight-binding Hamiltonian. This explains why the
UHF energies become nearly spin independent in this regime while the RHF
energies do not. The UHF densities display an even-odd effect which is related
to the angular momentum of the Wigner molecule. In a weak transversal magnetic
field this even-odd effect disappears.
