The observation and prediction of unusually depressed first excited 2^+_1 states in even-A neutron - rich isotopes of semi-magic Sn above 132Sn provide motivations for reviewing the problems related to the nuclear astrophysics in general. In the present work, the beta-decay rates of the exotic even Sn isotopes (134,136Sn) above the 132Sn core have been calculated as a function of temperature (T). In order to get the necessary ft values, B(GT) values corresponding to allowed Gamow Teller (GT-) beta-decay have been theoretically calculated using shell model. The total decay rate shows decrease with increasing temperature as the ground state population is depleted and population of excited states with slower decay rates increases. The abundance at each Z value is inversely proportional to the decay constant of the waiting point nucleus for that particular Z. So the increase in half-life of isotopes of Sn, like 136Sn, might have substantial impact on the r-process nucleosynthesis.
The total cross sections of the neutron radiative capture on 12B at astrophysical energies to the ground state of 13B have been calculated in the energy range of 10E-8 to 10 MeV within the framework of a modified potential cluster model with the classification of orbital states according to Young diagrams. Reaction rates in the temperature range of 0.01 to 10 T9 and their analytical parameterization were obtained. The calculated rates of 12B(n,gamma)13B excess the previous results by approximately to one order. Cross sections and reaction rates of 12C(n,gamma)13C are calculated and compared to…
We report here an empirical formalism for predicting the cross-sections of neutron-rich nuclei produced in fragmentation of relativistic \b{eta}-unstable neutron-rich projectiles in the mid-mass region. The formalism is based on the abrasion-ablation picture of the projectile fragmentation reaction. It has been shown that the formalism can accurately reproduce the experimental cross-section data for nuclei produced in the fragmentation of 132Sn. The formalism, it is shown, can also reproduce the experimental cross-sections of neutron-rich nuclei produced in the fragmentation of 129Xe fairly ac…
Neutron-rich Sr nuclei around N=60 exhibit a sudden shape transition from spherical ground state to strongly prolate-deformed. Recently, a lot of new insight into the structure of Sr isotopes in this region was gained through experimental studies of excited levels, transitions strengths and spectroscopic factors. In this work, a "classic" shell-model description of strontium isotopes from N=50 to N=58 is provided, using a natural valence space outside the 78Ni core. Both even-even and even-odd isotopes are adressed. In particular, spectroscopic factors are computed to shed more light on the st…
In this study, the artificial neural network method has been employed for the generation of the new two-body matrix elements which is used for pfg shell nuclei. For this purpose, jj44b interaction Hamiltonian has been considered as a source. After the generation of the new Hamiltonian, both, original and new generated, are tested on proton-rich Zn isotopes. According to the results, the calculated values are close to the each other. As well the results from new interaction (jj44b_nn) are closer to the available experimental values in some cases.
The mechanism of multinucleon transfer (MNT) reactions for producing neutron-rich heavy nuclei around N = 126 is investigated within two different theoretical frameworks: dinuclear system (DNS) model and isospin-dependent quantum molecular dynamics (IQMD) model. The effects of mass asymmetry relaxation, N=Z equilibration, and shell closures on production cross sections of neutron-rich heavy nuclei are investigated. For the first time, the advantages for producing neutron-rich heavy nuclei around N = 126 is found in MNT reactions based on 238U target. We propose the reactions with 238U target f…
Based on the realistic nuclear force of the high-precision CD-Bonn potential, we have performed comprehensive calculations for neutron-rich calcium isotopes using the Gamow shell model (GSM) which includes resonance and continuum. The realistic GSM calculations produce well binding energies, one- and two-neutron separation energies, predicting that $^{57}$Ca is the heaviest bound odd isotope and $^{70}$Ca is the dripline nucleus. Resonant states are predicted, which provides useful information for future experiments on particle emissions in neutron-rich calcium isotopes. Shell evolutions in th…
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…
First-forbidden $\mathbfβ$-decay rates, energy rates of $β$-delayed neutrons and probability of $β$-delayed neutron emissions for neutron-rich nickel isotopes
We demonstrate that the intricate energy spectrum of neutron-rich helium isotopes can be straightforwardly described by taking advantage of the low-energy properties of neutron-neutron interaction and the scale separation that is present in diluted dripline systems. By using arguments based on the halo effective field theory, we carry out a parameter reduction of the complex-energy configuration interaction framework in the $spd$ space, including resonant and scattering states. By adjusting only one parameter, the strength of the spin-singlet central neutron-neutron interaction, we reproduce e…
