The presence of a particle continuum, both of a resonant and non-resonant
character, can significantly impact spectroscopic properties of weakly bound
nuclei and excited nuclear states close to, and above, the particle emission
threshold. In the framework of the continuum shell model in the complex
momentum-plane, the so-called Gamow Shell Model, we discuss salient effects of
the continuum coupling on the one-neutron overlap integrals and the associated
spectroscopic factors in neutron-rich helium and oxygen nuclei. In particular,
we demonstrate a characteristic near-threshold energy dependence of the
spectroscopic factors for different l-waves. We show also that the realistic
radial overlap functions, which are needed for the description of transfer
reactions, can be generated by single-particle wave functions of the
appropriately chosen complex potential.Comment: 9 figures; 23 pages; corrected version; accepted in Nuclear Physics