Radial characteristics for nuclear states with weakly bound nucleons

The dipole transition densities as well as the radial pattern of partial widths for bound states embedded in the continuum, which are excited in the photonuclear reaction processes ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(γ,n) and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(γ,p), are investigated in the framework of the continuum shell model for radii up to 11 fm. The ${\mathit{d}}_{3/2}$ nucleons in the resonance states of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ are loosely bound. Their extension well beyond the nuclear surface is taken into account in a straightforward manner. The interaction of the incoming photon with the nucleons of the target nucleus takes place mainly in the surface region at about 3 fm. The surface character is caused, above all, by geometrical effects. The nucleons emitted originate mainly from the interior of the nucleus due to the strong correlations of the nucleons. By this, the shell-model approach is justified in spite of the large radial extension of the ${\mathit{d}}_{3/2}$ nucleons.