We calculate densities of excited states in the quasiparticle random-phase approximation (QRPA) with Skyrme interactions and volume pairing. We focus on low-energy peaks/bumps in the strength functions of a range of Ca, Ni, and Sn isotopes for $J^{\pi }=0^{+},1^{-}$, and $2^{+}$. We define an “emitted-neutron number,” which we then use to distinguish localized states from scattering-like states. The degree of delocalization either increases as the neutron-drip line is approached or stays high between the stability line and the drip line. In the $2^{+}$ channel of Sn, however, the low-lying states, not even counting surface vibrations, are still fairly well localized on average, even at the neutron drip line.

• Received 31 July 2006

DOI:https://doi.org/10.1103/PhysRevC.76.044320