Effects of the particle-particle channel on properties of low-lying vibrational states

Institut de Physique Nucl´eaire, CNRS-IN2P3, Universit´e Paris-Sud, F-91406 Orsay Cedex, France(Dated: November 15 2007)Making use of the finite rank separable approach for the quasiparticle random phase approximationenables one to perform nuclear structure calculations in very large two-quasiparticle spaces. Theapproach is extended to take into account the residual particle-particle interaction. The calculationsare performed by using Skyrme interactions in the particle-hole channel and density-dependentzero-range interactions in the particle-particle channel. To illustrate our approach, we study theproperties of the lowest quadrupole states in the even-even nuclei