[en] The status of the theoretical research on the compressional modes of finite nuclei and the incompressibility K_∞ of nuclear matter, is reviewed. It is argued that the recent experimental data on the Isoscalar Giant Monopole Resonance (ISGMR) allow extracting the value of K_∞ with an uncertainty of about ± 12 MeV. Non-relativistic (Skyrme, Goguy) and relativistic mean field models predict for K_∞ values which are significantly different from one another, namely ∼ 220-235 and 250-270 MeV respectively. It is shown that the solution of this puzzle requires a better determination of the symmetry energy at, and around, saturation. The role played by the experimental data of the Isoscalar Giant Dipole Resonance (ISGDR) is also discussed

[en] The damping of single-particle and collective motion in exotic isotopes is a new topic and its study may shed light on basic problems of nuclear dynamics. For instance, it is known that nuclear structure calculations are not able, as a rule, to account completely for the empirical single-particle damping. In this contribution, we present calculations of the single-particle self-energy in the case of the neutron-rich light nucleus ²⁸O, by taking proper care of the continuum, and we show that there are important differences with the case of nuclei along the valley of stability

[en] Recent exclusive measurements have provided new results on the particle decay of nuclear giant resonances, which is probably the only way to get detailed information about the wave function of these collective modes. 22 refs

[en] We have calculated the electric dipole strength distributions in the unstable neutron-rich oxygen isotopes ^18,20,22O, in a model which include up to four quasiparticle-type configurations. The model is the extension, to include the effect of the pairing correlations, of a previous model very successful around closed shell nuclei, and it is based on the quasiparticle-phonon coupling. Low-lying dipole strength is found, which exhausts between 5 and 10% of the Thomas-Reiche-Kuhn (TRK) energy-weighted sum rule (EWSR) below 15 MeV excitation energy, in rather good agreement with recent experimental data. The role of the phonon coupling is shown to be crucial in order to obtain this result

[en] We study the effects of collective modes on shell structure in nuclei near the neutron drip line close to ¹⁰Be and ²⁴O. Energy shifts in single-particle energies are evaluated by a particle-vibration coupling model. In the case of the ¹⁰Be core, the coupling to 2⁺ states is found to reduce the shell gap between 2s_1/2 and 1p_1/2 states. In the case of the ²⁴O core, the couplings to 3^- and 2⁺ states lead to a large energy gap between 2s_1/2 and 1d_3/2 states, in agreement with a recent experimental evidence of a new magic number at N=16 near the neutron drip line. In particular, the 3^- vibrations are found to play a crucial role to push down the energy of the 2s_1/2 state

No abstract available

[en] Mean field calculations of the isovector dipole and low-lying 2⁺, 3^- excitations, performed within the Skyrme-RPA and QRPA framework, are discussed. Examples are chosen among the neutron-rich nuclei of interest for present nuclear structure research. The relevance of the correlations beyond mean field, in particular of the contribution of the coupling with surface vibrations, is pointed out. We stress the importance of unifying the microscopic nuclear structure calculations and reaction models for a direct comparison of the theoretical predictions with the experimental data. In this context we show the effectiveness of the folding model, which can naturally accommodate the RPA transition densities

[en] We have recently introduced a new approach, which is meant to be a first step towards complete low-lying spectroscopy of odd-mass nuclei.In the first applications, we have limited ourselves to a magic core plus an extra neutron or proton. The model does not contain any free adjustable parameter, but is based on a Hartree-Fock (HF) description of particle states and Random Phase Approximation (RPA) calculations for core excitations. The model is an extension of previous Particle-Vibration Coupling (PVC) calculations. However, at variance with these, it also includes the coupling with non-collective core excitations and can also describe states of shell-model type. At present, we apply this model by using Skyrme functionals, which is a specific realization of Density Functional Theory (DFT) in nuclei. We will show results in the neutron-rich region, around Ca and Sn isotopes. We would like to focus on the relationship between this model and other implementations of DFT that are based on the idea of symmetry breaking and restoration. In particular, relationships between this model and the standard multi-reference DFT for configuration mixing will be addressed.This document is composed of an abstract and the slides of the presentation. (author)

[en] The electromagnetic response and photoemission spectrum of a linear carbon chain are obtained from ab initio calculations of its electronic structure and vibrational modes. Theoretical results are presented for a chain of 5 atoms for which the photoabsorption and photoemission spectra have been measured experimentally. The theory accurately accounts for the experimental observations

[en] We investigate the role the interweaving of surface vibrations and nucleon motion has on Cooper pair formation in spherical superfluid nuclei. This is done solving self-consistently the Dyson equation with the normal and anomalous density Green functions. Effective and realistic nucleon-nucleon interactions are used. It is found, that the pairing gap receives about equal contributions from the bare and from the induced interaction. It is furthermore found that the self-energy processes reduce the pairing gap by about 20%. The extreme cases of the ¹¹Li and ¹²Be nuclei are also discussed