Microscopic Double Folding Research Articles

Systematic calculations of reactions with exotic and stable nuclei to establish a unified theoretical approach

We report on systematical optical model (OM) and continuum discretized coupled channel (CDCC) calculations applied to describe the elastic scattering angular distributions of exotic and stable nuclei projectiles on heavy targets. Our optical potential (OP) is composed of the nuclear microscopic double folding S\~ao Paulo potential (SPP), derived from the nonlocal nature of the interaction, and the Coulomb dipole polarization (CDP) potential, derived from the semiclassical theory of Coulomb excitation. The OP is compared to the trivial equivalent local potential (TELP), extracted from CDCC calculations. The OM and CDCC predictions corroborate each other and account for important differences in the nuclei reaction mechanisms, which are directly related to their structural properties. Thus, OM and CDCC establish a common basis for analyzing or even predicting exotic and stable nuclei reactions.

Elastic Scattering with Double Folding Model: 8B+27Al

In the present work, the elastic scattering of the 8B+27Al reaction at two different energies have been examined using the microscopic double folding potential approximation within the framework of the optical model. The real part of the optical model has been obtained by using Fermi, Gaussian and Variational Monte Carlo (VMC) density distributions in the microscopic double folding model and the imaginary part has been taken as Woods-Saxon volume type. The results of our microscopic analysis are quite compatible with the experimental cross-section data. The reaction cross sections, the volume integrals of used potentials and their χ2/N errors have also been computed. This study is important in showing the effect of microscopically derived potentials in explaining the 8B+27Al experimental data published recently.

Elastic scattering for 6Li+51V and systematic study of breakup threshold anomaly

Elastic scattering for 6Li+51V system is measured around Coulomb barrier energies. The behavior of the nuclear potential is extracted from elastic scattering angular distributions measured in wide angular range. The data have been analyzed using phenomenological Woods-Saxon shaped optical potential and microscopic double folding potential frameworks. Sensitivity radius was determined using optical model and potential behavior thus analyzed shows breakup threshold anomaly (BTA). Continuum discretized coupled channel (CDCC) calculations give a good description of the measured elastic scattering data with breakup coupling effects. The contribution of breakup coupling through resonance states is significant. The potential behavior has been analyzed in the double folding framework using density distribution calculated from Hartree-Fock-Bogoliubov (HFB) method to understand the dependence of BTA in a wide mass range. It is observed that BTA exist from lower to higher mass targets for 6Li projectile. The systematic target dependence of the reaction cross-sections for 6Li projectile follows an universal scaling behavior. An enhancement in reaction cross section is observed for exotic compared to weakly and strongly bound projectiles with 51V target.

Experimental study of the energy dependence of the total cross section for the 6He + natSi and 9Li + natSi reactions

New experimental measurements of the total reaction cross sections for the 6He + natSi and 9Li + natSi processes in the energy range of 5 to 40 A MeV are presented. A modified transmission method based on high-efficiency detection of prompt n–γ radiation has been used in the experiment. A bump is observed for the first time in the energy dependence σR(E) at E ∼ 10–30 A MeV for the 9Li + natSi reaction, and existence of the bump in σR(E) at E ∼ 10–20 A MeV first observed in the standard transmission experiments is experimentally confirmed for the 6He + natSi reaction. Theoretical analysis of the measured 6He + natSi and 9Li + natSi reaction cross sections is performed within the microscopic double folding model. Disagreement is observed between the experimental and theoretical cross sections in the region of the bump at the energies of 10 to 20 A MeV, which requires further study.

Elastic scattering of the halo nucleus11Be on64Zn

Elastic scattering cross sections for the halo nucleus 11 Be incident on 64 Zn in vicinity of Coulomb barrier are calculated using the microscopic double folding model. The parametrized densities taking into account for the halo part are folded with the effec- tive nucleon-nucleon interaction (M3Y) to yield the microscopic double folded potential. The dynamic polarization potential has been computed using the dipole strength distri- bution from the cluster model and from experiments. The calculated differential cross section with the inclusion of the imaginary part of the dynamic polarization potential to the double folded potential show a suppression in the Coulomb-nuclear interference region.

FOLDING MODEL ANALYSIS OF 6He+120Sn ELASTIC SCATTERING

In this study, the elastic scattering of 6 He projectile from 120 Sn nucleus has been analyzed in terms of optical model (OM). Microscopic double folding (DF) model has been used to generate the real central part of the OM potential. The imaginary part has been restricted to Woods–Saxon phenomenological form. Skyrme–Hartree–Fock, Symmetrized Fermi and Gaussian-Exponential densities for 6 He nucleus while Hartree–Fock–Bogolyubov (HFB) density of 120 Sn nucleus have been used to construct the real DF potential. For the effective interaction, the widely used M3Y has been adopted in the DF procedure. The results of DF have been compared with both literature experimental data and phenomenological analysis.

A theoretical study on 120Sn(6He, 6He)120Sn elastic scattering

In this study, we analyze 120Sn(6He,6He)120Sn elastic scattering with both the phenomenological (WS) and microscopic double folding (DF) potentials. In the phenomenological calculations we use the optical model (OM) parameters acquired from literature. DF potentials have been obtained for no-core shell model (NCSM) density distribution (DD) of 6He nucleus. The phenomenological results is compared with DF model results as well as the experimental data. These comparison provides information about the similarities and differences of the models used in calculations.

Microscopic double folding potential description of the6He+12Creaction

We investigate the simultaneous explanation of the ${}^{6}\mathrm{He}+{}^{12}\mathrm{C}$ elastic and inelastic scattering and ${}^{6}\mathrm{He}+{}^{12}\mathrm{C}\ensuremath{\rightarrow}{}^{4}\mathrm{He}+{}^{14}\mathrm{C}$ transfer reaction observables at 18.0 MeV within the framework of the coupled-channels Born approximation. In obtaining the microscopic double folding potentials, two different nucleon densities deduced from the no-core shell model and few-body model calculations for the $^{6}\mathrm{He}$ have been used. Although a good agreement between theoretical results and experimental data has been obtained for elastic scattering and transfer reactions data, the theoretical results underestimate the magnitude of the inelastic-${2}^{+}$ state data. We present in this article that the deformation of the imaginary part of the optical potential is very important and it overcomes the magnitude problem for the inelastic data for this system.

Optical model potentials involving loosely boundp-shell nuclei around 10 MeV/nucleon

We present the results of a search for optical model potentials for use in the description of elastic scattering and transfer reactions involving stable and radioactive p-shell nuclei. This was done in connection with our program to use transfer reactions to obtain data for nuclear astrophysics, in particular for the determination of the astrophysical ${S}_{17}$ factor for ${}^{7}\mathrm{Be}(p,\ensuremath{\gamma}{)}^{8}\mathrm{B}$ using two ${(}^{7}\mathrm{Be}{,}^{8}\mathrm{B})$ proton transfer reactions. Elastic scattering was measured using ${}^{7}\mathrm{Li},$ ${}^{10}\mathrm{B},$ ${}^{13}\mathrm{C},$ and ${}^{14}\mathrm{N}$ projectiles on ${}^{9}\mathrm{Be}$ and ${}^{13}\mathrm{C}$ targets at or about $E/A=10\mathrm{M}\mathrm{e}\mathrm{V}/\mathrm{n}\mathrm{u}\mathrm{c}\mathrm{l}\mathrm{e}\mathrm{o}\mathrm{n}.$ Woods-Saxon type optical model potentials were extracted and are compared with potentials obtained from a microscopic double folding model. Several nucleon-nucleon effective interactions were used: M3Y with zero range and finite range exchange term, two density dependent versions of M3Y and the effective interaction of Jeukenne, Lejeune, and Mahaux. We find that the latter one, which has an independent imaginary part, gives the best description. Furthermore, we find the renormalization constant for the real part of the folding potential to be nearly independent of the projectile-target combination at this energy and that no renormalization is needed for the imaginary part. From this analysis, we are able to eliminate an ambiguity in optical model parameters and thus better determine the asymptotic normalization coefficient for ${}^{10}{\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}}^{9}\mathrm{B}+p.$ Finally we use these results to find optical model potentials for unstable nuclei with emphasis on the reliability of the description they provide for peripheral proton transfer reactions. We discuss the uncertainty introduced by the procedure in the prediction of the distorted wave Born approximation cross sections for the ${(}^{7}\mathrm{Be}{,}^{8}\mathrm{B})$ reactions used in extracting the astrophysical factor ${S}_{17}(0).$