The shell structure of even-even isotopes in Si, S, Ar and Ca has been analysed. The theoretical calculations of shell closure parameter $D_{n} (N)$ and the differential variation of the two-neutron separation energy $dS_{2n} (Z, N )$ are carried out within the framework of Hartree-Fock-Bogoliubov theory. Calculations are carried out for different skyrme forces and their sensitivity has been tested. Same nuclides are studied by employing the relativistic mean field aproach based on meson exchange and point coupling models. Theoretically calculated estimates are in good agreement with the recently available experimental data which fortifies signature of shell closure at N = 14 and 20 in case of Si, N = 14, 20 and 28 in S and N=20 and 28 in Ar and Ca isotopes.
The isoscaler giant monopole resonances (ISGMR) are computed using the canonical-basis time-dependent Hartree-Fock-Bogoliubov theory (Cb-TDHFB) with five kinds of Skyrme parameter sets (SGII, SkM$^*$, SLy4, SkT3 and SkI3). To extract the nuclear matter property from finite system, ISGMRs of $N$=$Z$ ($Z$=20 - 50), isobar even-even nuclide for $A$=100, 132 and Sn isotopes are analysed systematically. The magnitude relation of nuclear incompressibility-parameter ($K_\infty$) among Skyrme parameter sets, can be corresponded to the peak positions of GMR in spherical isotopes over $A$=80. The parame…
The production of neutron-rich isotopes and the occurrence of neutron capture cascades via laser-driven (pulsed) neutron sources are investigated theoretically. The considered scenario involves the interaction of a laser-driven neutron beam with a target made of a single type of seed nuclide. We present a comprehensive study over $95$ seed nuclides in the range $3\le Z \le 100$ from $^7_3$Li to $^{255}_{100}$Fm. For each element, the heaviest sufficiently-long-lived (half life $> 1$ h) isotope whose data is available in the recent ENDF-B-VIII.0 neutron sublibrary is considered. We identify int…
We consider the collinear ternary fission which is a sequential ternary decay with a very short time between the ruptures of two necks connecting the middle cluster of the ternary nuclear system and outer fragments. In particular, we consider the case where the Coulomb field of the first massive fragment separated during the first step of the fission produces a lower pre-scission barrier in the second step of the residual part of the ternary system. In this case, we obtain a probability of about $10^{-3}$ for the yield of massive clusters such as \nuclide[70]{Ni}, \nuclide[80-82]{Ge}, \nuclide…
The differences of the masses of nuclear isotopes with atomic numbers between \~10 and ~30 can be described within the chiral soliton approach in satisfactory agreement with data. Rescaling of the model is necessary for this purpose - decrease of the Skyrme constant by about 30%, providing the "nuclear variant" of the model. The asymmetric term in Weizsaecker-Bethe- Bacher mass formula for nuclei can be obtained as the isospin dependent quantum correction to the nucleus energy. Some predictions for the binding energies of neutron rich nuclides are made in this way, from, e.g. Be-16 and B-19 to…
We have calculated the multinucleon transfer reactions of $^{208}$Os, $^{208}$Pt, $^{208}$Hg, $^{208}$Pb,$^{208}$Po, $^{208}$Rn, $^{208}$Ra,$^{132,136}$Xe bombarding on $^{232}$Th and $^{248}$Cm at Coulomb barrier energies within the dinuclear system model, systematically. The results are in good agreement with the available experimental data. Coulomb effect and shell effect on production of actinides in these reactions have been investigated thoroughly. Potential energy surface and total kinetic energy mass distributions in the reactions $^{208}$Hg, $^{208}$Pb and$^{208}$Po colliding on $^{24…
We measure cross sections for residual nuclide formation in the mass range 6 < A < 97 caused by bombardment with protons and deuterons of 3.65 GeV/nucleon energy of enriched tin isotopes (112-Sn, 118-Sn, 120-Sn, 124-Sn). The experimental data are compared with calculations by the codes FLUKA, LAHET, CEM03, and LAQGSM03. Scaling behavior is observed for the whole mass region of residual nuclei, showing a possible multifragmentation mechanism for the formation of light products (6 < A < 31). Our analysis of the isoscaling dependence also shows a possible contribution of multifragmentation to the…
The recently confirmed neutron-shell closure at N = 32 has been investigated for the first time below the magic proton number Z = 20 with mass measurements of the exotic isotopes 52,53K, the latter being the shortest-lived nuclide investigated at the online mass spectrometer ISOLTRAP. The resulting two-neutron separation energies reveal a 3 MeV shell gap at N = 32, slightly lower than for 52Ca, highlighting the doubly-magic nature of this nuclide. Skyrme-Hartree-Fock-Boguliubov and ab initio Gorkov-Green function calculations are challenged by the new measurements but reproduce qualitatively t…
The creation of transuranium nuclides under pulsed neutron fluxes of thermonuclear explosions is investigated within the kinetic model of the astrophysical r process, taking into account the time dependence of the external parameters and the processes accompanying the beta decay of neutron-rich nuclei. Time-dependent neutron fluxes in the interval ~ 10e-6 s were modeled within the framework of the developed adiabatic binary model. The probabilities of beta-delayed processes were calculated on the base of the microscopic theory of finite Fermi systems. Calculations of transuranium nuclides yiel…
Calculations of inclusive $α$ particle production are performed to interpret reaction experimental data induced by the two-neutron halo $^6$He and the isotopes $^{6,7}$Li on different target nuclei. We have implemented the zero-range post-form DWBA to compute the elastic and nonelastic breakup cross sections. Integrated cross sections, angular distributions and spectra are presented. Projectiles are approximated as two-body clusters, namely $^6$He as $α$+dineutron and $^{6}$Li ($^{7}$Li) interpreted as $α$+deuteron(triton). The São Paulo optical potential is employed in the calculation of the …
Four groups (even-even, even-odd, odd-even and odd-odd) of heavy and super-heavy nuclei are of interest for the synthesis of the isotopes with $Z=119, 120$. We report calculations of $α$~decay half-lives using four models: AKRA (Akrawy); ASAF (Analytical Super-Asymmetric Fission); UNIV (Universal Formula), and semFIS (Semi-empirical formula based on Fission Theory). We compare the experimental $Q_α$ values either with AME16 atomic mass evaluation (whenever available) and with the theoretical model WS4, able to give masses of not yet measured nuclides. For $^{92,94}$Sr cluster radioactivity of …
The region around the doubly magic nuclide $^{100}Sn$ is very interesting for nuclear physics studies in terms of structure, reaction and nuclear astrophysics. The main ingredients in nuclear structure studies using the shell model are the single-particle energies and the two-body matrix elements. To obtain the former, experimental data of $^{101}Sn$ isotope spectrum are necessary. Since there is not enough experimental data, different approaches are used in the literature to obtain single-particle energies. In sn100pn interaction, the hole excitation spectrum was used in $^{131}Sn$ to determi…
We present our recent study of cross sections and angular distributions of projectile fragments from heavy-ion reactions at beam energy of 15 MeV/nucleon. We studied the production cross sections and the angular distributions of neutron-rich nuclides from collisions of a 86 Kr (15 MeV/nucleon) beam with heavy targets ( 64 Ni, 124 Sn and 238 U). Experimental data from our previous work at Texas A & M were compared with model calculations. Our calculations were based on a two-step approach: the dynamical stage of the collision was described with, first, the phenomenological Deep-Inelastic Transf…
One of the main ingredients in nuclear structure studies using shell model are the single-particle energy (spe). In order to obtain these values accurately, experimental data is needed. The region around the doubly magic nuclide 100Sn is very interesting for nuclear studies in terms of structure, reaction and nuclear astrophysics. Experimental spectrum data for the 101Sn isotope is required for nuclear shell model studies to be carried out in this region. Since there is not enough experimental data in the literature, different approaches are used for the obtaining spes for the region such as u…
We identify here possible occurrence of large deformations in the neutron- and proton-rich regions of the nuclear chart from extensive predictions of the values of the reduced quadrupole transition probability B-E2 for the transition from the ground state to the first 2+ state and the corresponding excitation energy E2 of even-even nuclei in the recently developed Generalized Differential Equation model exclusively meant for these physical quantities. This is made possible from our analysis of the predicted values of these two physical quantities and the corresponding deformation parameters de…
Energy levels and electromagnetic properties of with $N=28\sim 30$ nuclides are studied in terms of a large-scale shell model calculation, which contains no newly adjusted parameters. The Kuo-Brown $G$-matrix interaction is shown to reproduce energy levels of 205 low-lying states of these nuclei. We evaluate effective charges by incorporating the core-polarization effects caused by the coupling to GQR's. We then compute E2 moments and transition probabilities. The M1 moments and transition rates are calculated by quoting the effective $g$-factors of Towner, which are obtained by taking into ac…
The acquisition of precise and reliable nuclear data is a prerequisite to success for stellar evolution and nucleosynthesis studies. Core-collapse simulators find it challenging to generate an explosion from the collapse of the core of massive stars. It is believed that a better understanding of the microphysics of core-collapse can lead to successful results. The weak interaction processes are able to trigger the collapse and control the lepton-to-baryon ratio ($Y_{e}$) of the core material. It is suggested that the temporal variation of $Y_{e}$ within the core of a massive star has a pivotal…
We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: the dynamical stage of the collision is described with either the phenomenological Deep-Inelastic Transfer model (DIT), or with the microscopic Constrained Molecular Dynamics model (CoMD). The deexcitati…
Accurate estimate of neutrino energy loss rates are needed for the study of the late stages of the stellar evolution, in particular for cooling of neutron stars and white dwarfs. The energy spectra of neutrinos and antineutrinos arriving at the Earth can also provide useful information on the primary neutrino fluxes as well as neutrino mixing scenario (it is to be noted that these supernova neutrinos are emitted after the supernova explosion which is a much later stage of stellar evolution than that considered in this paper). Recently an improved microscopic calculation of weak-interaction med…
Nuclear properties across the chart of nuclides are key to improving and validating our understanding of the strong interaction in nuclear physics. We present high-precision mass measurements of neutron-rich Fe isotopes performed at the TITAN facility. The multiple-reflection time-of-flight mass spectrometer (MR-ToF-MS), achieving a resolving power greater than $600\,000$ for the first time, enabled the measurement of $^{63-70}$Fe, including first-time high-precision direct measurements ($δm/m \sim 10^{-7}$) of $^{68-70}$Fe, as well as the discovery of a long-lived isomeric state in $^{69}$Fe.…
Magnetic dipole strength functions are determined for the series of germanium isotopes from $N = Z = 32$ to $N$ = 48 on the basis of a large number of transition strengths calculated within the shell model. The evolution of the strength with increasing neutron number in the $1g_{9/2}$ orbital is analyzed. A bimodal structure comprising an enhancement toward low transition enery and a resonance in the region of the scissors mode is identified. The low-energy enhancement is strongest near closed shells, in particular at the almost completely filled $1g_{9/2}$ orbital, while the scissorslike reso…
This paper presents our recent efforts to study the momentum distributions as well as the production of neutron-rich rare isotopes with heavy-ion beams in the energy region of 15 MeV/nucleon. Experimental cross sections of neutron-rich nuclides from collisions of a 86 Kr (15 MeV/nucleon) beam with 64 Ni and 58 Ni targets are presented. Experimental data were obtained from the previous work of our group with the MARS mass spectrometer at the Cyclotron Institute of Texas A&M University. On that note, detailed calculations of yields and momentum distributions of neutron-rich projectile-like fragm…
This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for $^{54,55,56}$Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase app…
We present freshly evaluated B$(E2\uparrow;0^+\rightarrow2^+)$ values across the even-even Sn-isotopes which confirm the presence of an asymmetric behavior as well as a dip in the middle of the full valence space. We explain these features by using the concept of generalized seniority. The dip in the B$(E2)$ values near $^{116}$Sn is understood in terms of a change in the dominant orbits before and after the mid shell, which also explains the presence of asymmetric peaks in the B$(E2)$ values. This approach helps in deciding the most active valence spaces for a given set of isotopes, and singl…
The evolution of the pairing correlations from closed shell to middle shell nuclei is analyzed with a Finite Range Density Dependent interaction in the Sn isotopes. As theoretical approaches we use the Hartree-Fock-Bogoliubov, the Lipkin-Nogami, their particle number projected counterparts and the full variation after particle number projection method. We find that whereas all approaches succeed rather well in the description of the total energy they differ significantly in the pairing correlation content of the wave functions. The description of the evolution from the weak to the strong pairi…
The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A = 124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the ELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIgS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of m…
Neutron star mergers offer unique conditions for the creation of the heavy elements and additionally provide a testbed for our understanding of this synthesis known as the $r$-process. We have performed dynamical nucleosynthesis calculations and identified a single isotope, $^{254}$Cf, which has a particularly high impact on the brightness of electromagnetic transients associated with mergers on the order of 15 to 250 days. This is due to the anomalously long half-life of this isotope and the efficiency of fission thermalization compared to other nuclear channels. We estimate the fission fragm…
The available data for E2 transition strengths in the region between neutron-deficient Hf and Pt isotopes are far from complete. More and precise data are needed to enhance the picture of structure evolution in this region and to test state-of-the-art nuclear models. In a simple model, the maximum collectivity is expected at the middle of the major shell. However, for actual nuclei, this picture may no longer be the case, and one should use a more realistic nuclear-structure model. We address this point by studying the spectroscopy of Hf. We remeasure the 2^+_1 half-lives of 172,174,176Hf, for…
