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In this brief report, we make a short review of progress in developing the microscopic optical potential in recent years. In particular, we present our current studies and plans on building the microscopic optical potential based on the so-called nuclear structure models at low energies.

The present paper reports on the spin-parities and the magnetic moments for the ground states of 44 proton-rich isotopes with Z = 21–30 and A = 36–57, which are important for studies of either reaction rates in X-ray bursts or nuclear structure. These nuclear properties were calculated based on the single-particle shell model. The spins of the concerned nuclei were compared to available experimental data adopted from the NuDat database to evaluate the variations in the astrophysical rates of the rp-process reactions. We found discrepancies, due to the deformed nuclear structure, between the present results and those reported in the NuDat database. The spin uncertainties result in large variations, 13%–200%, in the astrophysical rates of the rp-process reactions. In particular, the spin uncertainties of the 44V and the 46–49Mn isotopes significantly affect the astrophysical rates of the reverse reactions of the proton captures 43Ti(p, γ)44V(p, γ)45Cr, 45Cr(p, γ)46Mn(p, γ)47Fe, 47Mn(p, γ)48 Fe, 47Cr(p, γ)48 Mn(p, γ)49 Fe, and 48Cr(p, γ)49 Mn(p, γ)50 Fe. Moreover, the magnetic moments of most of the isotopes were predicted for the first time. The results show that the magnetic moments are in the order of μp(1f7/2) > μp(2p3/2) > μn(1d3/2) > μp (1f7/2)for thenuclei having an unpaired nucleon in the proton/neutron shells. The present study suggests that reliable calculations and/or measurements for the properties of proton-rich nuclei are highly demanded.

The properties of the scattering solutions obtained as poles of the $S$ and $K$ matrices are analyzed in terms of pairing effects in the framework of the Hartree-Fock-Bogoliubov (HFB) Jost function. As a result of our analysis, we found the following: in order for the poles of the $S$ matrix to form a resonance, there must be a pole of the $K$ matrix nearby. Within the framework of HFB theory, there are three types of resonance states; shape resonances, particle-type, and hole-type quasiparticle resonances. Other scattering states that can be classified are independent $K$- and $S$-matrix poles. It is shown both numerically and qualitatively using the Jost function that the pair-correlation effect is hardly observed in the shape resonance state, and that the appearance of the pair-correlation effect is different in the particle-type and hole-type quasiparticle resonance. We also found a noteworthy correlation effect that independent $K$-matrix poles break the metastable structure of the wave function of the quasiparticle resonance and turn it into an independent $S$-matrix pole. The correlation effect that the poles of the independent $S$ matrix break the metastable structure of the inner wave function without breaking the resonance structure of the outer wave function when a pole of the independent $S$ matrix is near the hole-type resonance state was also revealed. This is considered to be another aspect of the Fano effect.

In this paper, nanostructured Ni-doped LaFeO3 materials were prepared via a simple co-precipitation method involving the hydrolysis of La(III), Fe(III), and Ni(II) cations in hot water with 5% KOH as a precipitating agent. To evaluate the effects of Ni substitution in these products, their structural phases, lattice parameters, crystallite and grain sizes, and magnetic properties were determined. As the Ni content in the LaFe1-xNixO3 (x = 0–0.25) materials increased, the average crystallite size and lattice parameters decreased. Moreover, across the range of Ni-substitution ratios, all magnetic properties correspondingly changed: the coercive force (Hc) value rose from 42.53 to 173.98 Oe. In contrast, the remanent magnetization (Mr) and saturation magnetization (Ms) values decreased from 1.0· × 10⁻2 to 3.8· × 10⁻4 emu g⁻1, and from 0.24· × 10° to 0.74· × 10⁻4 emu g⁻1, respectively. These predictable changes provide a sound foundation for the fabrication and application of magnetic materials based on nanostructured Ni-doped LaFeO3 substrates.

A fully microscopic model for the description of nuclear level density (NLD) in spherical nuclei is proposed. The model is derived by combining the partition function of the exact pairing solution plus the independent-particle model at finite temperature (EP+IPM) with that obtained by using the collective vibrational states calculated from the self-consistent Hartree-Fock mean field with MSk3 interaction plus the exact pairing and random-phases approximation (SC-HFEPRPA). Two important factors are taken into account in a fully microscopic way, namely the spin cut-off and vibrational enhancement factors are, respectively, calculated using the statistical thermodynamics and partition function of the SC-HFEPRPA without any fitting parameters. The numerical test for two spherical $^{60}$Ni and $^{90}$Zr nuclei shows that the collective vibrational enhancement is mostly dominated by the quadrupole and octupole excitations. This is the first microscopic model confirming such an effect, which was phenomenologically predicted long time ago and widely employed in several NLD models. In addition, the influence of collective vibrational enhancement on nuclear thermodynamic quantities such as excitation energy, specific heat capacity and entropy is also studied by using the proposed model., 7 pages, 3 figures, accepted in Phys. Lett. B

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

Gamma spectrum measured by an NaI(Tl) detector is known to be unstable with the in situ temperature. In the present work, an advanced method has been applied to stabilize the gamma spectrum measured by the NaI(Tl) detector at environmental radiation monitoring (ERM) stations. The method is based on experimental data obtained under controlled conditions in laboratory. In the temperature range from 4 to 45°C, the relative deviation of the peak positions within the stabilized gamma spectrum is less than 2%. To test this method in a real scenario, it has been integrated into the ERM station at the Military Institute of Chemical and Environmental Engineering in Hanoi, Vietnam. The results show that the proposed method is ready for a real application.

We formulate the Jost function formalism based on the Hartree-Fock-Bogoliubov (HFB) theory which has been used to represent the nature of nuclear superfluidity. By using the Jost function based on the HFB, the $S$-matrix for the neutron elastic scattering by the open-shell nucleus can be represented analytically. Adopting the Woods-Saxon potential, we calculate the $S$-matrix poles and their trajectories by varying the pairing strength using the Jost function in order to see the pairing effect on the complex energy-momentum plane. The total cross sections of neutron elastic scattering are also analyzed, and some sharp or asymmetrical resonances (from the configuration mixing) due to the pairing effect are found in the cross section.

In this study the classical three-dimensional ensemble model is utilized for investigating the role of final state electron-electron repulsion in forming the ultimate correlated two-electron momentum distribution. For the first time, a comprehensive analysis has been made to thoroughly understand such repulsive force associating with each microscopic mechanism of nonsequential double ionization. The helium exposed to 800-nm laser with two representative intensities of 3.5×1014 W/cm2 and 4.5×1014 W/cm2 is used for illustration. The results indicate the dominance of electron-electron repulsion in direct and recollision-induced excitation with subsequential ionizations. While its contribution in case of exchanging-state mechanism gradually emerges as the laser intensity increases.

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 this contribution we make a short review of recent progress on topics of current interest in nuclear physics and nuclear astrophysics. In particular, we discuss a re-analysis of the extraction of the dipole response of the pigmy resonance in $^{68}$Ni based on a continuum discretized coupled-channels calculation in relativistic Coulomb excitation experiments. We also discuss the forthcoming progresses made by our group on the Alt-Sandhas-Grassberber approach to (d,p) reactions and future expectations. The role of separable potentials in solving such equations with a test case based on applications of such potentials to phase-shift analysis is also presented., Carpathian Summer School of Physics 2016,Exotic Nuclei and Nuclear/Particle Physics VI, "Physics with small accelerators", eds. L. Trache et al. 9 pages, 6 figures

The dipole excitations for calcium and zirconium isotopes are studied within the fully self-consistent Hartree-Fock mean field incorporated with the renormalized random-phase approximation (RRPA) using the Skyrme interaction SLy5. The RRPA takes into account the effect of ground-state correlations beyond RPA owing to the Pauli principle between the particle-hole pairs that form the RPA excitations as well as the correlations due to the particle-particle and hole-hole transitions, whose effects are treated here in an effective way. By comparing the RPA results with the RRPA ones, which are obtained for isoscalar (IS) and isovector (IV) dipole excitations in $^{48, 52, 58}$Ca and $^{90, 96, 110}$Zr, it is shown that ground-state correlations beyond the RPA reduce the IS transition strengths. They also shift up the energy of the lowest IV dipole state and slightly push down the peak energy of the IV giant dipole resonance. As the result, the energy-weighted sums of strengths of both IS and IV modes decrease, causing the violation of the corresponding energy-weight sum rules (EWSR). It is shown that this sum rule violation can be eliminated by taking into account the contribution of the particle-particle and hole-hole excitations together with the particle-hole ones in a simple and perturbative way. Consequently, the ratio of the energy-weighted sum of strengths of the pygmy dipole resonance to that of the giant dipole resonance increases., Comment: 23 pages, 2 figures, accepted in Physical Review C

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

International audience; Gold nanoparticles have been reported as a possible radio-sensitizer agent in radiation therapy due totheir ability to increase energy deposition and subsequent direct damage to cells and DNA within theirlocal vicinity. Moreover, this increase in energy deposition also results in an increase of the radiochemicalyields. In this work we present, for the first time, an in silico investigation, based on the general purposeMonte Carlo simulation toolkit Geant4, into energy deposition and radical species production around aspherical gold nanoparticle 50 nm in diameter via proton irradiation. Simulations were preformed forincident proton energies ranging from 2 to 170 MeV, which are of interest for clinical proton therapy.

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.

Two systematic sources of error in most current microscopic evaluations of fission-barrier heights are studied. They are concerned with an approximate treatment of the Coulomb exchange terms (known as the Slater approximation) in the self-consistent mean-fields and the projection on good parity states (e.g., of positive parity for the spontaneous fission of an even–even nucleus) of left–right reflection asymmetric intrinsic solutions (e.g., around the second barrier). Approximate or unprojected solutions are shown to lead each to an underestimation of the barrier heights by a few hundred keV.