Charge-Exchange Excitations with Skyrme Interactions in a Separable Approximation

Starting from a Skyrme interaction we propose an extension of the finite rank separable approximation for the case of charge-exchange nuclear modes. This approximation enables one to reduce considerably the dimensions of the matrices that must be diagonalized to perform QRPA calculations in very large configuration spaces. First, we check that the approximation reproduces reasonably well the full charge-exchange RPA results of the spindipole resonances in the nuclei 90 Zr and 132 Sn. The approach is then applied to the study of the Gamow-Teller and the spin-dipole resonances in the neutron-rich Cd isotopes, within the quasiparticle random phase approximation. Subject Index: 210, 213