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Elastic scattering of a series of doubly closed-shell nuclei at low energy has been described in the framework of optical potential model generated from the particle-vibration coupling approach on top of the collective excited states obtained from the random-phase approximation. We focus on the effects of the spin-orbit and velocity-dependent interaction on the angular distributions and analyzing powers by comparing these observables with experimental data. It has been found that the contribution of the two-body velocity-dependent and two-body spin-orbit terms are important to improve results for $^{16}\mathrm{O},\phantom{\rule{0.16em}{0ex}}^{40}\mathrm{Ca},\phantom{\rule{0.16em}{0ex}}^{48}\mathrm{Ca}$, and $^{208}\mathrm{Pb}$. The velocity-dependent interactions strongly reduce the absorption on the surface while the spin-orbit interactions sightly increase the absorption in the interior.

By focusing on the asymmetric shape of cross section, we analyze the pairing effect on the partial wave components of cross section for neutron elastic scattering off stable and unstable nuclei within the Hartree-Fock-Bogoliubov (HFB) framework. Explicit expressions for Fano parameters $q_{lj}$ and $\epsilon_{lj}$ have been derived and the pairing effects have been analyzed in term of these parameters, and the Fano effect was found on the neutron elastic scattering off the stable nucleus in terms of the pairing correlation. Fano effect was appeared as the asymmetric line-shape of the cross section caused by the small absolute value of $q_{lj}$ due to the small pairing effect on the deep-lying hole state of the stable nucleus. In the case of the unstable nuclei, the large $q_{lj}$ value is expected because of the small absolute value of the Fermi energy. The quasiparticle resonance with the large $q_{lj}$ forms the Breit-Wigner type shape in the elastic scattering cross section., Comment: Submitted to Physical Review C

At low-energy nuclear physics facilities, the in-flight fragmentation method is often employed to produce radioactive ion beams. This technique often involves a stable ion beam at high intensity and a gas cell target. Since the parameters for the production reaction are usually chosen to take advantage of a large cross section of the resonance reaction, a slight change in the center-of-mass energy due to the reduced target density may significantly affect the rare isotope production rate. Therefore, to estimate the heating effect due to beam particles on the target thickness, a new and more comprehensive semi-empirical model is developed by employing a heating factor function. The estimated heating factors were consistent with experimental data, which were obtained from various reaction measurements at wide ranges of heat densities.

In this work, we present a derivation of cross sections for single ionization and electron capture processes within the Classical Trajectory Monte Carlo (CTMC) approach. Specifically, we have used a potential stemming from an ab initio calculation in Green et al.’s framework to describe the dynamics of the water molecule system. Proposing a modified version of the Classical Over-Barrier (COB) potential, we have found that a cut-off of roughly 28 a.u. on the initial distance of the projectile produced a reasonable accuracy. A global agreement has been obtained in our calculations compared to experimental and other theoretical results for C6+ ion energies ranging from 10 keV/u to 10 MeV/u.

Background: Fission barriers of actinide nuclei have been mostly and for long been microscopi- cally calculated for even-even fissioning systems. Calculations in the case of odd nuclei have been performed merely within a so-called equal-filling approximation (EFA) as opposed to an approach taking explicitly into account the time reversal breaking properties at the mean field level- and for only one single-particle configuration. Purpose: We study the dependence of the fission barriers on various relevant configurations (e.g. to evaluate the so-called specialization energy). Besides, we want to assess the relevance as a func- tion of the deformation of the EFA approach which has been already found out at ground state deformation. Methods: Calculations within the Hartree-Fock plus BCS with self-consistent particle blocking have been performed using the SkM* Skyrme effective interaction in the particle-hole channel and a seniority force in the particle-particle channel. Axial symmetry has been imposed throughout the whole fission path while the intrinsic parity symmetry has been allowed to be broken in the outer fission barrier region. Results: Potential energy curves have been determined for six different configurations in U-235 and four in Pu-239. Inner and outer fission barriers have been calculated along with some spectroscopic properties in the fission isomeric well. These results have been compared with available data. The influence of time-reversal breaking mean fields on the solutions has been investigated. Conclusions: A sizeable configuration dependence of the fission barrier (width and height) has been demonstrated. A reasonable agreement with available systematic evaluations of fission barrier heights has been found. The EFA approach has been validated at the large elongations occurring at the outer barrier region., 25 pages, 11 figures, accepted for publication in PRC

In four well-deformed heavy odd nuclei, the energies of low-lying rotational band heads have been determined microscopically within a self-consistent Hartree-Fock-plus-BCS approach with blocking. A Skyrme nucleon-nucleon effective interaction has been used together with a seniority force to describe pairing correlations. Only such states which are phenomenologically deemed to be related to single-particle excitations have been considered. The polarization effects, including those associated with the genuine time-reversal symmetry breaking have been fully taken into account within our model assumptions. The calculated spectra are in reasonably good qualitative agreement with available data for the considered odd-neutron nuclei. This is not so much the case for the odd-proton nuclei. A potential explanation for such a difference in behavior is proposed.

Using the $R$-matrix approach we calculate the radiative width for a resonance decaying to a bound state through electric dipole, $E1$, transitions. The total radiative width is determined by the interference of the nuclear internal and external radiative width amplitudes. For a given channel radius the external radiative width amplitude is model independent and is determined by the asymptotic normalization coefficient (ANC) of the bound state to which the resonance decays. It also depends on the partial resonance width. To calculate the internal radiative width amplitude we show that a single particle potential model is appropriate. We compare our results with a few experimental data., Comment: Version accepted for publication in Phys. Rev. C

The description of nucleons scattering off doubly closed-shell nuclei $^{16}\mathrm{O}$ and $^{208}\mathrm{Pb}$ at energies below 50 MeV is carried out in a fully self-consistent framework of the particle-vibration coupling approach. The applications are performed with commonly used Skyrme-type effective interactions. Nucleon-nucleus optical potentials are thus calculated without ad hoc adjusted parameters. These potentials are then solved with standard optical model codes (dwba98 in the present case). Empirical nucleon-nucleus elastic angular distributions are thus successfully reproduced.

The restoration of parity symmetry has been performed in the framework of the highly truncated diagonalization approach, which is suited to treat correlations in an explicitly particle-number-conserving microscopic approach. To do so we have assumed axial symmetry and used a generalized Wick's theorem attributable to L\"owdin in a projection-after-variation scheme. We have chosen the Skyrme SkM${}^{*}$ energy-density functional for the particle-hole channel and a density-independent $\ensuremath{\delta}$ force for the residual interaction. We have applied this approach in the region of the outer fission barrier of the ${}^{240}$Pu nucleus. As a result, we have shown that the ${K}^{\ensuremath{\pi}}={0}^{+}$ fission isomeric state is statically unstable against intrinsic parity-breaking modes, while the projection does not affect the energy at the top of the intrinsic outer fission barrier. Altogether, this leads to an increase of the height of the outer fission barrier, with respect to the fission isomeric state, by about 350 keV, thus affecting significantly the spontaneous-fission half-life of the considered fission isomer.