  The Green's function method in the \emph{Quasiparticle Time Blocking
Approximation} is applied to nuclear excitations in $^{132}$Sn and $^{208}$Pb.
The calculations are performed self-consistently using a Skyrme interaction.
The method combines the conventional RPA with an exact single-particle
continuum treatment and considers in a consistent way the particle-phonon
coupling. We reproduce not only the experimental values of low- and high-lying
collective states but we also obtain fair agreement with the data of
non-collective low-lying states that are strongly influenced by the
particle-phonon coupling.
