Investigation of probable decays in Rhenium isotopes

Physical Review C

The α-decay half-lives of some superheavy nuclei within a modified generalized liquid drop model (MGLDM) have been studied. The computed half-lives are compared with experimental data and also with existing theoretical models as well as the Royer, AKRE, New RenB, and Akrawy formulas, and are found to be in good agreement. Also, we have calculated the RMS deviation. We expect the present investigation is a clear indicator of the predictive power of the model and formulas, which may be helpful for future investigations in this field.

Nuclear physics a, 2022

The alpha decay, the cluster radioactivity and the heavy particle emission half-lives of known and some still unknown superheavy nuclei have been investigated within the original Generalized Liquid Drop Model and analytic formulas. The Q value has been calculated mainly from the recent NUBASE2020 tables. The agreement between the experimental data and the theoretical predictions of the alpha decay half-lives of the superheavy nuclei is correct and some predictions are provided for unknown nuclei. For some emissions of heavy particles by superheavy nuclei the half-life is comparable to the alpha decay half-lives or even smaller.

2015

Over the last 66 years numerous determinations have been made of the 187Re half-life and decay constant. With the measurement technology having improved, the determinations over the last 20 years have resulted in close agreement between the four determination methods—direct physical counting and in-growth experiments, and radioisotope age comparisons using molybdenites and groups of meteorites. Thus the 187Re half-life and decay constant values of 41.577 ± 0.12 Byr and 1.6668 ± 0.0034 × 10-11 per year respectively have now been adopted for standard use by the uniformitarian geological community. These values are based on determinations recalibrating Re-Os model ages of molybdenites by forcing them (essentially by circular reasoning) to agree with the U-Pb concordia-Pb-Pb intercept ages of zircons from the same 11 magmatic-hydrothermal systems dating from ca. 90 Ma to ca. 2670 Ma. This value is essentially identical to the best of the recent determinations using groups of iron meteor...

Phys. Rev. C 79 054330, 2009

The proton radioactivity half-lives of spherical proton emitters are investigated theoretically. The potential barriers preventing the emission of protons are determined in the quasimolecular shape path within a generalized liquid drop model (GLDM) including the proximity effects between nuclei in a neck and the mass and charge asymmetry. The penetrability is calculated with the WKB approximation. The spectroscopic factor has been taken into account in half-life calculation, which is obtained by employing the relativistic mean field (RMF) theory combined with the BCS method with the force NL3. The half-lives within the GLDM are compared with the experimental data and other theoretical values. The GLDM works quite well for spherical proton emitters when the spectroscopic factors are considered, indicating the necessity of introducing the spectroscopic factor and the success of the GLDM for proton emission. Finally, we present two formulas for proton emission half-life calculation similar to the Viola-Seaborg formulas and Royer's formulas of α decay.

Physical Review C

Theoretical half-lives of α decay for lead (Pb) isotopes (Z = 82) in the range 178 A 220 systematically have been investigated within the modified generalized liquid drop model (MGLDM). Akrawy, Royer, AKRE, and Modified RenB formulas are used to evaluate α-decay half-lives. The experimental Q values are used. The results are compared with the experimental data and with Coulomb and proximity potential model. The standard deviations are evaluated; the results indicate that the MGLDM and Akrawy are the best model and formula for evaluating α decay for Pb isotopes.

Physical Review C, 2022

Background: The cluster radioactivity from the neutron-deficient trans-tin region of the nuclear landscape has given immediate attention in the nuclear structure studies. Recent prediction of the emitting clusters from the ground and intrinsic excited states of proton-rich Ba isotopes opens the direction to explore the corresponding decay characteristics. A theoretical probe is necessary for understanding the cluster decays of Ba isotopes. Purpose: In the present study, cluster-decay half-lives are calculated and their decay characteristics are investigated for even-even 112-122 Ba isotopes in both ground and intrinsic excited states along the proton drip line. Method: The preformed-cluster-decay model (PCM) is employed for estimating the decay half-lives. The preformation probability (P 0) of the cluster decay from the parent nuclei is calculated by using the well-known phenomenological formula of Blendowske and Walliser [Phys. Rev. Lett. 61, 1930 (1988)], supplemented with the newly proposed Q-value-based preformation factor for the cluster with mass A c > 28. The penetration probability is calculated from the interaction potential using the Wentzel-Kramers-Brillouin (WKB) approximation. The nucleon-nucleon (NN) potential and individual binding energy (BE) of the cluster and daughter nuclei are estimated from the microscopic relativistic mean-field formalism (RMF) and compared with those from experiments and the finite-range-droplet model for the estimation of the Q values of the cluster decays. The nonlinear RMF Lagrangian from which the effective relativistic R3Y NN potential is derived using the NL3 * parameter set is employed for the calculation of the nuclear matter densities. The R3Y and well-known M3Y potential are employed to obtain the cluster-daughter interaction potential using the double-folding procedure along with their corresponding RMF densities. The total potential along with their respective cluster decay Q values are used as input in the PCM to obtain the half-lives (T 1/2) of 112-122 Ba isotopes in their ground and intrinsic excited states. Results: The calculated half-lives (T 1/2) for relativistic R3Y NN potential and Q values are found to deviate slightly compared to the ones from the M3Y due to the difference in their barrier characteristics. We notice that at elongated neck configuration a minimum neck-length parameter R = 1.0 fm is required for R3Y potential due to its repulsive nature, whereas the value is 0.5 fm is suitable for the M3Y case. However, the estimated decay half-lives for both the potentials are in reasonably good agreement with the experimental lower limit of 114 Ba. In contrast with the ground-state decays, the inclusion of intrinsic excitation reduces the corresponding half-life values considerably but does not rule out the role of magicity. Conclusions: The sensitivity of the decay half-lives to Q values and neck-length parameter has also been demonstrated. The decay half-lives are predicted for various cluster decays from neutron-deficient Ba isotopes. Since none of the experimental half-lives for the examined clusters is precisely known yet, further studies with available observed half-lives will be needed to substantiate our findings.

Physical Review C, 2013

The β-decay properties of several neutron-rich germanium and arsenic isotopes were measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The measurements of almost-pure radioactive sources were enabled by the combination of ion-source chemistry and two-stage mass separation. The half-life of 86 Ge (226 ± 21 ms) was determined for the first time, while those of 84,85 Ge and 84−87 As were remeasured. The results are compared to theoretical predictions of the gross theory of β decay, the finite-range droplet model, and the new calculations using the energy density functional DF3a with continuum quasiparticle random-phase approximation (CQRPA). We confirm the robustness and good predictive power of the latter model for nuclei near closed shells. These DF3a + CQRPA calculations were used recently to analyze r-process isobaric abundances.

Nuclear Physics A, 2010

From an adjustment on a recent selected data set of partial α-decay half-lives of 344 ground state to ground state transitions, analytical formulas are proposed for log 10 T 1/2 (s) depending or not on the angular momentum of the α particle. In particular, an expression allows to reproduce precisely the partial α-decay half-lives of even-even heavy nuclei and, then, to predict accurately the partial α-decay half-lives of other very heavy elements from the experimental or predicted Q α. Comparisons have been done with other empirical approaches. Moreover, the potential barrier against α-decay or α-capture has been determined within a liquid drop model including a proximity energy term. Simple expressions are provided to calculate the potential barrier radius and height.

2019

We have studied the nuclear properties and life-time of few proton emitters in their ground state using spherical densities obtained from effective field theory motivated relativistic mean field formalism (E-RMF) for two recent parameter sets G3 and IOPB-I. We have found that these emitters have binding energy per nucleon near the iron peak but due to the inadequate number of neutrons, the Coulomb force cannot be compensated completely hence, the nucleus breaks down. Experimental Q-value is used for the calculate of proton emission half-life using WKB approximation. It is noticed that for suitable l-values our results meet the experimental half-lives. This study enhances our understanding on the nuclear force and shell structure in the drip line region.

Physical Review C, 2013

The β-decay properties of several neutron-rich germanium and arsenic isotopes were measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The measurements of almost-pure radioactive sources were enabled by the combination of ion-source chemistry and two-stage mass separation. The half-life of 86 Ge (226 ± 21 ms) was determined for the first time, while those of 84,85 Ge and 84−87 As were remeasured. The results are compared to theoretical predictions of the gross theory of β decay, the finite-range droplet model, and the new calculations using the energy density functional DF3a with continuum quasiparticle random-phase approximation (CQRPA). We confirm the robustness and good predictive power of the latter model for nuclei near closed shells. These DF3a + CQRPA calculations were used recently to analyze r-process isobaric abundances.