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In this paper, the nuclear structure and some prospective decay properties of the 128−208Sm62 elements are studied. This is accomplished by using an axially deformed oscillator basis and the Relativistic Mean Field model (RMF) with PK1 and NL-SH force parameters. The bulk characteristics are carefully examined, including the binding energy (B.E./A), nuclear radii,quadrupole deformation parameter(β2), two neutron separation energy (S2n), and differential change of two neutron separation energy (dS2n). Estimates are also made for the half-lives of the Sm isotopes for α-decay, β-decay and spontaneous fission (SF). Both our computed Q-values and empirically measurable Q-values are used to determine the α-decay half-life periods using the MUDL and AKRE formulae. The results we anticipate could be useful for experiments and future perspective. [ABSTRACT FROM AUTHOR]

β decay has played a key role in studies of shape coexistence throughout the nuclear chart. This has been mainly due to the sensitivity in γ -ray and conversion electron spectroscopy that can be achieved following the population of excited states by β decay. In some regions, the spectroscopic studies using β decay have been the first to suggest the presence of shape coexistence; in others, they have reinforced the suggestion and provided important spectroscopic data. The present work reviews some of the key regions, with a prime focus on the neutron-rich side of the valley of stability, where β -decay measurements have played an important role. [ABSTRACT FROM AUTHOR]

The determination of the β intensity probability between the ground states of parent and daughter nuclei has traditionally been a difficult task with standard γ -spectroscopy approaches due to the lack of the associated γ emission. In the last years, the total absorption γ -ray spectroscopy technique has successfully proven its ability to deal with this problem by means of different procedures. This article discusses the potential of these methods, and a new approach for segmented total-absorption γ -ray spectrometers is also introduced. An overview of applications is presented based on past, present, and future β -decay experiments. [ABSTRACT FROM AUTHOR]

The nuclear β -decay half-lives of Ni and Sn isotopes, around the closed shell nuclei 78 Ni and 132 Sn, are investigated by computing the distribution of the Gamow–Teller strength using the Quasiparticle Random Phase Approximation (QRPA) with quasiparticle-vibration coupling (QPVC), based on ground-state properties obtained by Hartree–Fock–Bogoliubov (HFB) calculations. We employ the effective interaction SkM ⁎ and a zero-range effective pairing force. The half-lives are strongly reduced by including the QPVC. We study in detail the effects of isovector (IV) and isoscalar (IS) pairing. Increasing the IV strength tends to increase the lifetime for nuclei in the proximity of, but lighter than, the closed-shell ones in QRPA calculations, while the effect is significantly reduced by taking into account the QPVC. On the contrary, the IS pairing mainly plays a role for nuclei after the shell closure. Increasing its strength decreases the half-lives, and the effect at QRPA and QRPA+QPVC level is comparable. The effect of IS pairing is particularly pronounced in the case of the Sn isotopes, where it turns out to be instrumental to obtain good agreement with experimental data. [ABSTRACT FROM AUTHOR]

β -decay studies of neutron-rich nuclei in and around the “island of inversion” have been performed. With a systematic investigation of half-lives for the isotonic chains from N = 19 to 22, conspicuous kinks observed at Z = 13 provide a clear signature of a boundary on the northern (high- Z ) side of the island. Based on the comparison with shell model calculations using Gogny D1S and SDPF-M interactions, a newly determined 2 2 + state in 34 Si at 4519 keV presents an experimental evidence of triaxiality in this region and sheds more light on the structure of the transition across the northern boundary of the island. [ABSTRACT FROM AUTHOR]

The first evidence for β -delayed proton emission from the 16 + spin gap isomer in 96 Cd is presented. The data were obtained from the Rare Isotope Beam Factory, at the RIKEN Nishina Center, using the BigRIPS spectrometer and the EURICA decay station. βp branching ratios for the ground state and 16 + isomer have been extracted along with more precise lifetimes for these states and the lifetime for the ground state decay of 95 Cd. Large scale shell model (LSSM) calculations have been performed and WKB estimates made for ℓ = 0 , 2 , 4 proton emission from three resonance-like states in 96 Ag, that are populated by the β decay of the isomer, and the results compared to the new data. The calculations suggest that ℓ = 2 proton emission from the resonance states, which reside ∼ 5 MeV above the proton separation energy, dominates the proton decay. The results highlight the importance of core-excited wavefunction components for the 16 + state. [ABSTRACT FROM AUTHOR]

We investigated the effects of first-forbidden transitions in β decays on the production of the r -process A ∼ 195 peak. The theoretical calculated β -decay rates with β -delayed neutron emission were examined using several astrophysical conditions. As the FF decay is dominant in N ∼ 126 neutron-rich nuclei, their inclusion shortens β -decay lifetimes and shifts the abundance peak towards higher masses. Additionally, the inclusion of the β -delayed neutron emission results in a wider abundance peak, and smoothens the mass distribution by removing the odd–even mass staggering. The effects are commonly seen in the results of all adopted astrophysical models. Nevertheless there are quantitative differences, indicating that remaining uncertainty in the determination of half-lives for N = 126 nuclei is still significant in order to determine the production of the r -process peak. [ABSTRACT FROM AUTHOR]

We review several theoretical models based on the introduction of a mean-field that have been applied systematically to superheavy nuclei. The models that are considered are the macroscopic–microscopic approach and self-consistent mean-field models, based either on non-relativistic or on relativistic energy density functionals. A few examples illustrate results of beyond mean-field methods that explicitly consider collective correlations related to the symmetry restoration and fluctuations in the collective coordinates. We discuss in detail the evolution of the ground state shape and of α -decay with N and Z as predicted by the different models and compare them with experimental data. Finally, we present a brief account of predictions concerning β -decay. [ABSTRACT FROM AUTHOR]