A self-consistent study of multipole response in neutron-rich nuclei using a modified realistic potential

Abstract

The multipole response of neutron rich O and Sn isotopes is computed in\nTamm-Dancoff and random-phase approximations using the canonical\nHartree-Fock-Bogoliubov quasi-particle basis. The calculations are performed\nusing an intrinsic Hamiltonian composed of a $V_{lowk}$ potential, deduced from\nthe CD-Bonn nucleon-nucleon interaction, corrected with phenomenological\ndensity dependent and spin-orbit terms. The effect of these two pieces on\nenergies and multipole responses is discussed. The problem of removing the\nspurious admixtures induced by the center of mass motion and by the violation\nof the number of particles is investigated. The differences between the two\ntheoretical approaches are discussed quantitatively. Attention is then focused\non the dipole strength distribution, including the low-lying transitions\nassociated to the pygmy resonance. Monopole and quadrupole responses are also\nbriefly investigated. A detailed comparison with the available experimental\nspectra contributes to clarify the extent of validity of the two\nself-consistent approaches.\n