  Advances in the self-consistent Green's function approach to finite nuclei
are discussed, including the implementation of three-nucleon forces and the
extension to the Gorkov formalism. We report results on binding energies in the
nitrogen and fluorine isotopic chains, as well as spectral functions of 22O.
The application to medium-mass open-shell systems is illustrated by separation
energy spectra of two argon isotopes, which are compared to one-neutron removal
experiments.
