Engineering topics

De Donno, V

Publications and source records attributed to De Donno, V.

4 records

DOE OSTI2011

Self-consistent continuum random-phase approximation calculations of {sup 4}He electromagnetic responses

We study the electromagnetic responses of {sup 4}He within the framework of the self-consistent continuum random-phase approximation theory. In this approach, the ground-state properties are described by a Hartree-Fock calculation. The single-particle basis constructed in this manner is used in the calculations of the continuum responses of the system. Finite-range interactions are considered in the calculations. We compare our results with photon-absorption cross sections and electron-scattering quasielastic data. From this comparison, and also from the comparison with the results of microscopic calculations, we deduce that our approach describes well the continuum excitation.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2011

Quasifree (e,e{sup '}p) reactions on nuclei with neutron excess

We study the evolution of the (e,e{sup '}p) cross section on nuclei with increasing asymmetry between the number of neutrons and protons. The calculations are done within the framework of the distorted-wave impulse approximation, by adopting nonrelativistic and relativistic models. We compare the results obtained with three different approaches based on the mean-field description for the proton bound-state wave function. In the nonrelativistic model phenomenological Woods-Saxon and Hartree-Fock wave functions are used; in the relativistic model the wave functions are solutions of Dirac-Hartree equations. The models are first tested against experimental data on {sup 16}O, {sup 40}Ca, and {sup 48}Ca nuclei, and then they are applied to calculate (e,e{sup '}p) cross sections for a set of spherical calcium and oxygen isotopes. From the comparison of the results obtained for the various isotopes we can infer information about the dependence of the various ingredients of the models on the neutron to proton asymmetry.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2011

Tensor effective interaction in self-consistent random-phase approximation calculations

We present a study of the effects of the tensor-isospin term of the effective interaction in Hartree-Fock and random-phase approximation calculations. We used finite-range forces of Gogny type, and we added to them a tensor-isospin term which behaves, at large internucleonic distances, as the analogous term of the microscopic interactions. The strength of this tensor force has been chosen to reproduce the experimental energy of the lowest 0{sup -} excited state in {sup 16}O, which shows large sensitivity to this term of the interaction. With these finite-range interactions, we have studied the effects of the tensor-isospin force in ground and excited states of carbon, oxygen, calcium, nickel, zirconium, tin, and lead isotopes. Our results show that the tensor force affects mainly the nucleon single-particle energies. However, we found some interesting cases where also bulk nuclear properties are sensitive to the tensor interaction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2011

Self-consistent continuum random-phase approximation calculations with finite-range interactions

We present a technique that treats, without approximations, the continuum part of the excitation spectrum in random phase approximation calculations with finite-range interactions. The interaction used in Hartree-Fock calculations to generate the single-particle basis is also used in continuum random phase approximation calculations. We show results for electric dipole and quadrupole excitations in {sup 16}O, {sup 22}O, {sup 24}O, {sup 40}Ca, {sup 48}Ca, and {sup 52}Ca nuclei. We compare our results with those of the traditional discrete random phase approximation, with continuum independent-particle model results, and with results obtained by a phenomenological random phase approximation approach. We study the relevance of the continuum, of the residual interaction, and of the self-consistency. We also compare our results with the available total photoabsorption cross-section data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗