Excitations of pygmy dipole resonances in exotic and stable nuclei via Coulomb and nuclear fields

摘要

We study heavy-ion inelastic scattering processes in neutron-rich nuclei including the full response to thendifferent multipolarities. Among thesewe focus in particular on the excitation of low-lying dipole states commonlynassociated to the pygmy dipole resonance. The multipole response is described within the Hartree-Fock plus RPAnformalism with Skyrme interaction.We show how the combined information from reactions processes involvingnthe Coulomb and different mixtures of isoscalar and isovector nuclear interactions can provide a clue to revealnthe characteristic features of these states. We have performed calculation for the excitation of 132Sn generated innthe reactions with 4He, 40Ca, and 48Ca at several incident energies, as well as for the system 17O + 208Pb. Ournresults suggest that the investigation of the PDR states can be better carried out at low incident energies (belown50 MeVucleon). In fact, at these energies the PDR peak is relatively stronger than the giant dipole resonancen(GDR) one and the narrow width of the low-lying quadrupole and octupole states should not blur its presence.