Universal Decay Law Research Articles

Favored one proton radioactivity within a one-parameter model* *Supported by National Natural Science Foundation of China (Grant No.12175100 and No. 11705055), the construct program of the key discipline in Hunan province, the Research Foundation of Education Bureau of Hunan Province, China (Grant No. 18A237), the Innovation Group of Nuclear and Particle Physics in USC, the Shandong Province Natural Science Foundation,

In the present work, a phenomenological one-parameter model (OPM) based on the Wentzel-Kramers-Brillouin (WKB) theory is applied to study the favored one proton radioactivity (the orbital angular momentum l taken away by the emitted proton is equal to zero) half-lives. The calculated results can reproduce the experimental data well within a factor of ∼3. In addition, we extend the OPM to predict the half-lives of possible favored one proton radioactivity nuclei whose decay is energetically allowed or observed but not quantified in NUBASE2020. For comparison, a universal decay law of one proton radioactivity (UDLP) is also used. It is obviously found that our predicted results are close to the ones using UDLP. The predictions are helpful for searching for the new nuclides with favored one proton radioactivity.

Systematic calculations of cluster radioactivity half-lives in trans-lead nuclei* *This work is supported in part by the National Natura Science Foundation of China (12175100 and 11975132), the Construct Program of the Key Discipline in Hunan Province, the Research Foundation of Education Bureau of Hunan Province (18A237), the Natural Science Foundation of Hunan Province (2018JJ3324), the Innovation Group of Nuclear and

In the present work, based on the Wentzel-Kramers-Brillouin (WKB) theory, considering the cluster preformation probability (), we systematically investigate the cluster radioactivity half-lives of 22 trans-lead nuclei ranging from 221Fr to 242Cm. When the mass number of the emitted cluster 28, is obtained by the exponential relationship of to the α decay preformation probability () proposed by R. Blendowskeis [Phys. Rev. Lett. 61, 1930 (1988)], while is calculated through the cluster-formation model (CFM). When 28, is calculated through the charge-number dependence of on the decay products proposed by Ren [Phys. Rev. C 70, 034304 (2004)]. The half-lives of cluster radioactivity have been calculated by the density-dependent cluster model [Phys. Rev. C 70, 034304 (2004)] and by the unified formula of half-lives for alpha decay and cluster radioactivity [Phys. Rev. C 78, 044310 (2008)]. For comparison, a universal decay law (UDL) proposed by Qi [Phys. Rev. C 80, 044326 (2009)], a semi-empirical model for both α decay and cluster radioactivity proposed by Santhosh [J. Phys. G: Nucl. Part. Phys. 35, 085102 (2008)], and a unified formula of half-lives for alpha decay and cluster radioactivity [Phys. Rev. C 78, 044310 (2008)] are also used. The calculated results of our work, Ni's formula , and the UDL can well reproduce the experimental data and are better than those of Santhosh's model. In addition, we extend this model to predict the half-lives for 51 nuclei, whose cluster radioactivity is energetically allowed or observed but not yet quantified in NUBASE2020.

Unified description of α decay and cluster radioactivity using the neural network approach and universal decay law

The α decay and cluster radioactivity half-life of nuclei are calculated uniformly. The universal decay law (UDL) (Qi et al 2009 Phys. Rev. Lett. 103 072501) is refitted to include minimum angular momentum effect and unpaired nucleon effect. The UDL formula and neural network approach to describe α decay and cluster radioactivity half-life calculations were improved. We used the UDL formulas and neural network approach to predict the cluster radioactivity half-life of actinide nuclei and α decay half-life of superheavy nuclei Z = 117–120. We hope to contribute to the discovery of new atomic nucleus cluster radioactivity phenomena and theoretical studies of α decay of superheavy nuclei.

Clustering effect in description of the alpha and heavier decay half-life

We examine the alpha and heavier cluster decay half-lives of the nuclei for 87 ≤ Z ≤ 96 using the analytical formula obtained by the Wentzel-Kramers-Brilliouin (WKB) method within the framework of the cluster model for the modified harmonic oscillator and spherical Coulomb potential. We correlate the clustering effect in the nuclei with the nuclear potential depth only and systematically investigate the alpha and heavier cluster decay half-lives. In addition to half-lives, the branching ratios relative to alpha decay half-lives are also calculated and results are compared with experimental data. The rms deviations of the alpha and cluster decay half-lives show a good agreement with the universal decay law (UDL), Horoi and one single line of universal (UNIV) curve models. Utilizing the optimized cluster model parameters, we also predict the half-lives of 14C, 20O, 24,25Ne, 28,30Mg and 32Si cluster emissions from various isotopes for guiding future experiments.

Systematic study on α-decay half-lives of uranium isotopes with a screened electrostatic barrier* *Supported in part by the National Natural Science Foundation of China (12175100, 11975132), the Construct Program of the Key Discipline in Hunan Province, the Research Foundation of Education Bureau of Hunan Province, China (21B0402, 18A237), the Natural Science Foundation of Hunan Province, China (2018JJ2321), the Innovation Group

In the present work, we systematically study the α-decay half-lives of uranium (Z=92) isotopes based on the Gamow model with a screened electrostatic barrier. There are only two adjustable parameters in our model i.e. the parameter g and the screening parameter t in the Hulthen potential for considering the screened electrostatic effect of the Coulomb potential. The calculated results are in good agreement with experimental data, and the corresponding root-mean-square (rms) deviations of uranium isotopes with α transition orbital angular momentum l=0 and l=2 are 0.141 and 0.340, respectively. Moreover, we extend this model to predict α-decay half-lives of uranium isotopes whose α decay is energetically allowed or observed but not yet quantified in NUBASE2020. For comparison, the modified Hatsukawa formula (XLZ), the unified Royer formula (DZR), the universal decay law (UDL) and the Viola–Seaborg–Sobiczewski formula (VSS) are also used. The predictions are basically consistent with each other. Meanwhile, the results also indicate that N=126 shell closure is still robust at Z=92 and the spectroscopic factor is almost the same for uranium isotopes with the same l.

Temperature dependence of cluster decay

A universal decay law (UDL) for light cluster decay of excited nuclei is formulated by fitting the UDL half-lives to those evaluated within an excitation energy-dependent double folding model (DFM). The half-lives are evaluated within a preformed cluster model. The excitation energy dependence is introduced both in the energy of the emitted cluster and in the interaction potential through the density distributions of the interacting nuclei. The half-lives are found to decrease when the difference between the excitation energies of the parent and daughter nuclei, ΔE⁎> 0, increases, with the reduction being a few orders of magnitude for higher values of ΔE⁎. This can be of importance for nucleosynthesis calculations of heavy elements formed in extremely hot environments, as well as in highly energetic heavy-ion collisions. The UDL for excited nuclei is used to provide an estimate of the enhancement in the cluster decay rates of thermally excited nuclei such as those produced in r-process nucleosynthesis.

Nonlocality effect in α decay of heavy and superheavy nuclei

The $\ensuremath{\alpha}$-decay half-life of heavy and superheavy nuclei has been investigated using a potential barrier penetration model that adapts semiclassical WKB calculations to incorporate a coordinate-dependent effective mass for the $\ensuremath{\alpha}$ particle. This effect is a consequence of a dynamic property of nonlocality in the particle-nucleus interaction, as implemented in the barrier tunneling calculations of [N. Teruya, S. B. Duarte, and M. M. N. Rodrigues, Phys. Rev. C 93, 024606 (2016)]. Calculations have been performed for a recent set of experimental data of 255 $\ensuremath{\alpha}$-emitting nuclides, all selected with angular momentum $\ensuremath{\ell}=0$ experimentally assigned. Results show a good agreement when compared to experimental half-life data, obtaining a standard deviation of $\ensuremath{\sigma}=0.306$ and fully satisfying the universal systematics, namely, new universal plot and universal decay law systematics, of $\ensuremath{\alpha}$ decay. Additionally, the present model has been applied to make half-life predictions for 34 possible new $\ensuremath{\alpha}$-decay cases.

Structure and Decay Properties of Th Isotopes Using E-RMFT Formalism

In the present scenario, the search for the thermally fissile nuclei is crucial and also important not only for the research background of nuclear physics but also for the great social and economic impact on the country. Many theoretical works have been performed to analyze a series of Th and U-isotopes and found that some of these isotopes are stable against α-decays and spontaneous fission. Here, we have chosen the isotopic chain of Th-nuclei for the present analysis using relativistic mean-field formalism. The work also explores a few stable isotopes in this region of the nuclear landscape, which is crucial for understanding the exotic region of the nuclear landscape. The objective of this work is to study the bulk properties such as binding energies, root mean square charge radii, neutron-proton radii, neutron skin-thickness as well as intrinsic properties such as excitation energy and specific heat for the 216-238 Th-isotopic chain. Furthermore, the stability of these isotopes is investigated through their possible decay chain analysis. The relativistic mean-field theory was used to obtain the nuclear bulk properties, namely, binding energies, root-mean-square charge radii, neutron skin-thickness, and excitation energy. The steady solution of the temperature-dependent effective relativistic mean-field equations was obtained self-consistently by taking different inputs of the initial deformations. All the calculations were done for NL3, FSUGarnet and IOPB-I parameter sets for 216-238 Th-isotopes. The decay energy of α (Q α ) and β-decay (Q β ) were calculated from the binding energies and were further used to obtain the corresponding half-lives. We have analyzed the structural and decay properties of 216-238 Th isotopes. The excitation energy and specific heat are also estimated for these considered nuclei by using the temperature-dependent effective relativistic mean-field (E-RMFT) formalism for NL3, FSUGarnet and IOPB-I parameters sets. The calculated results are compared with the available experimental data and found similar observations for all the parameter sets at a given temperature. The excitation energy study signifies the shell melting point where maybe the shape transition occurs. Three phenomenological formulae such as Viola-Seaborg, Royer and modified universal decay law are adopted for the calculation of α-decay half-lives. We found lower values of α-decay half-lives indicating a higher rate of β-decay for the isotopic chain.

Structure and decay chain of fermium isotopes using relativistic mean-field approach

In this paper, we have analyzed the ground state structural properties of fermium-isotopes in the mass range [Formula: see text] within the relativistic mean-field with NL3[Formula: see text] and Relativistic Hartree–Bogoliubov approach with DD-ME2 parameter sets. The bulk properties, such as binding energy, root mean-square charge radius, quadruple deformation parameter, chemical potentials, two-neutron separation energy and differential two- neutron separation energy, are estimated for the above Fm- isotopic chain. All the calculated observables are compared with finite range droplet model (FRDM) predictions and experimental data wherever available. The analysis predicts the existence of shell closure in the neutron-rich region of the isotopic chain at [Formula: see text]. The decay properties such as the [Formula: see text]-decay energy and corresponding half-life for three decay chains i.e. [Formula: see text]Fm, [Formula: see text]Fm and [Formula: see text]Fm are studied. Six different empirical formulae, namely; Viola-Seaborg, Royer, modified B. Alex Brown, Parkhomenko–Sobiczewski, Universal decay law and modified universal decay law are employed to ascertain the numerical dependency of the half-life for each decay energy. A comparative study of [Formula: see text]-values and half-lives for these decay chains gives a good signature of the calculated results. The half-life calculations of three decay chains suggest that [Formula: see text]Pu, [Formula: see text]Pu, [Formula: see text]Pu are shell closure nuclei having maximum half-lives, whereas [Formula: see text]Fm, [Formula: see text]Fm and [Formula: see text]Fm are shell stabilized with lower half-lives.

Cluster radioactivity around shell closures: correlation of half-lives with the energy levels of daughter nuclei

The emission of Be, C, O, and Ne clusters from seven parent nuclei with neutron numbers around the neutron magicities N = 82 and 126 are considered. The universal decay law (UDL) formula, as well as the double-folding model derived from the Michigan three-range Yukawa–Paris NN interaction with zero- and finite-range exchange components, are utilized to compute the half-life time for 23 cluster decay processes. The calculations utilizing the UDL formula show satisfactory agreement with the experimental data. The reliable UDL formula is used to calculate log T c for more than 1500 cluster emitters and its variation with the neutron number, N d, of the daughter nuclei is presented. The behavior of log T c with neutron number variation is studied and correlated to the energy levels of the daughter nuclei. For a neutron number N d larger than the neutron magic number, log T c increases almost linearly with increasing N d, leaving the daughter nuclei in most cases with the same nuclear spin value. This linear behavior of log T c results from equal nuclear spin values of the daughter nuclei. At the magic neutron number, the nuclear spin changes strongly and as a result log T c increases as N d decreases. Log T c reaches to a maximum value when all the neutrons in the cluster are emitted from levels below the neutron gap. Leaving the daughter nuclei in the same spin produces almost linear variation of log T c. For protons in various clusters emitted from the same level or the same group of levels, log T c has almost the same value and the same behavior of variation with N d. Also, the values of log T c for specific types of cluster depend on the N to Z ratio for different isotopes of this cluster. From the available nuclear spin values, the neutron energy levels around the magic numbers are presented.

Theoretical description of the decay width of neutron emission in light nuclei

<p indent="0mm">The study of nuclear decay is an important field for investigating nuclear structures and nucleosynthesis. The existence of Coulomb interaction makes the emission of charged particles have a relatively long half-life. Based on the WKB approximation and the R-matrix method, several empirical formulas describing the proton decay, alpha decay, and emission of charged clusters have been proposed, e.g., the new Geiger-Nutall formula and the Universal Decay Law. The investigation of beta delayed proton(s) decay enhances understanding of isospin symmetry breaking and mixing. Because of the absence of Coulomb interaction, the half-life of neutron emission is much shorter. For neutron-unbound states, the experimentalists concentrate more on discovering neutron-rich nuclei beyond the neutron-drip line. The theorists are more interested in establishing models for a specific nucleus to describe the one- and two-neutron emission phenomenon. The universal law describing the general characteristics of single neutron emission is rarely taken into account. This paper applies the WKB approximation and the R-matrix method to investigate the decay width of the single neutron emission. The square well potential and the harmonic oscillator potential are used as input of nuclear potential. As to the R-matrix method, the sine function basis and the Lagrange basis are applied, respectively. Both the WKB approximation and the R-matrix method calculate the decay width in two parts: The formation factor and the penetration factor. A three-variable formula is deduced from the penetration factor of these two theories. As to the ground states emitting a single neutron, the root-mean-square of log₁₀<italic>Γ</italic>_exp/<italic>Γ</italic>_cal for the three-variable formula is only 0.31, which shows a good description ability. The decay widths of the other 13 nuclides are thus predicted. For the excited states, the direct application of the two theories presents deviation within an order of about 3. The decay width is found to be sensible to the radius of nuclear force and less sensible to the depth of nuclear potential according to the comparison between the square well potential and the harmonic oscillator potential. The hard-core effect is intrinsically considered by the R-matrix method, compared with the WKB approximation, which shows an overall overestimation. After removing such an overestimation, the deviation of the WKB approximation is reduced to be in the order of about 0.8. The three-variable formula shows better description capability, and the deviation is reduced to be in the order of 0.56. The suggested formula is the first try to describe the decay width of a single neutron emission well, which is beneficial to further investigate the characteristics of nuclei near the neutron drip line. Moreover, the influence of spin-orbit interaction, the tensor force, and the shell effect can be taken into account for amelioration. Besides, the fission products of heavy nuclei are generally in highly excited states and will be deexcited through beta decay, emitting neutrons, etc. The neutron emission and beta-delayed neutron emission in these processes are important for the chain reaction and the control of the nuclear reactor. For further investigation, the results of this paper will be extended and applied to the region of nuclear fission products.

Predictions of the alpha-decay half-lives of even–even superheavy nuclei using modified Gamow-like model

α-decay half-lives of superheavy nuclei have been studied using modified Gamow-like model and improved empirical formulas. The empirical formulas used in the study are Viola-Seaborg semi-empirical formula, universal decay law (UDL), Denisov-Khudenko formula (DK), Royer formula, Wang formula, AKRE formula, and new Ren B (NRB) formula. New values of the adjustable parameters in the modified Gamow-like model have been obtained using a least square fit scheme and input data from the NUBASE2020 database. We found that only two adjustable parameters are sufficient to describe the α-decay half-lives of heavy and superheavy nuclei. We also obtained new coefficients for the seven empirical formulas using similar procedure. The modified Gamow-like model (MGLM) and improved empirical formulas are then used to calculate the α-decay half-lives of measured superheavy nuclei with Z = 100–118. The calculated root mean square errors indicate that the Royer, DK, and AKRE formulas are the best three empirical formulas for evaluating the α-decay half-lives of the superheavy nuclei. The five best performing empirical formulas, together with the MGLM, are then used to predict alpha-decay half-lives of unmeasured even–even superheavy nuclei with Z = 120–126. The Q α values used for the predictions have been taken from the tabulated Weizs cker-Skyrme-4 + RBF (WS4 + RBF) Q α values. The theoretical calculations suggest that N = 184 is a possible magic number, which is in agreement with previous theoretical calculations.

Study of cluster emissions from heavy nuclei using an empirical formula and the Coulomb and Proximity potential model for deformed nuclei

The decay characteristics of various clusters and neutron halo nuclei from heavy elements [Formula: see text] are studied within the framework of the Coulomb and Proximity Potential Model for Deformed Nuclei (CPPMDN) and using a new empirical formula proposed by us. The predictive power of our formula is verified by comparing the predictions with the available experimental data and with the predictions of other models such as CPPM, Universal Decay Law of Qi et al. (UDL), Unified Description formula (UD) of Ni et al. Using the present formula and CPPMDN, decay half-lives of various light clusters from heavy elements are calculated, and the results are compared with the predictions of UDL, UD, and predictions made by Santhosh et al. based on the Modified Generalized Liquid Drop Model (MGLDM). The decay half-lives of halo nuclei from heavy elements are also calculated using the new formula and CPPMDN and compared with the predictions of UDL, UD, and the predictions made by Santhosh et al. based on the Coulomb and Proximity Potential Model (CPPM).

Structure and decay modes study of Th, U, and Pu isotopes using relativistic mean field model

In the present work, we have studied the structural properties, alpha and clusters (8Be, 12C, 16O, 20Ne, and 24Mg) decay half-lives for the Th, U, and Pu isotopes using the well-known Relativistic Mean-Field (RMF) theory with NL3* parameter set. We calculate the binding energy per nucleon, root-mean-square (rms) radii, two-neutron separation energies (S2n), and other observables. The results are in good agreement with the finite-range droplet model (FRDM) and experimental data. Using the calculated mass defect results from these calculations, the Effective liquid drop model (ELDM) has been used to determine alpha and cluster decay half-lives. The half-lives calculations are also carried out by using the latest empirical relations, namely Universal Decay Law (UDL), TM, VS, and the Scaling Law was given by Horoi et al., and their comparisons with ELDM results are found to be in good agreement. In the plots for log10T1/2 versus the neutron number of the daughter nucleus Nd in the corresponding decay, the half-life is found to have a minimum for the decay leading to nearly doubly magic or doubly magic daughter 208Pb nucleus (Nd=126). The Geiger-Nuttal plots for different clusters from various cluster radioactive (CR) emitters have been studied and they clearly show a linear behavior.

Research on α-decay for the superheavy nuclei with Z= 118–120 * *Partly supported by the National Natural Science Foundation of China (11935001,11575002), the Key Research Foundation of Education Ministry of Anhui Province (KJ2018A0028), and Anhui project (Z010118169)

The generalized liquid-drop model (GLDM) with the microscopic shell correction from relativistic Hartree-Fock (RHF) calculations is used to explore the α-decay of superheavy nuclei. The known nuclei with are chosen as examples for testing. The calculated half-lives of α-decay agree with the experimental data better than those from the GLDM with the shell correction in the Weizs cker-Skyrme model. Moreover, the influence of the decay energy on α-decay is investigated. It is determined that the values obtained from the WS4 model with radial basis function (RBF) correction match the experimental data optimally. Owing to these advantages, the GLDM with the RHF shell correction and WS4+RBF values is adopted to predict the α-decay lifetime for the unknown superheavy nuclei with . The trend of the available α-decay half-lives according to the neutron number is similar to the trends of the values from the GLDM calculation without shell correction as well as the universal decay law (UDL) formula. Comparably, the RHF shell correction depresses (raises) the α-decay lifetime for most nuclei with ( ). In comparison with the half-lives of spontaneous fission, it can be concluded that the α-decay is dominant in the superheavy nuclei , , and . These results are beneficial to the exploration of superheavy nuclei in experiments.

Exploring the ground state bulk and decay properties of the nuclei in superheavy island

The α-decay half-lives of 204 superheavy nuclei covering the range 114≤Z≤126 have been investigated using the relativistic mean-field model (RMF) for NL3⁎ parameter set. The ground state bulk properties such as binding energy, quadrupole deformation parameter (β2), and root-mean-square charge radii for these nuclei are analyzed. Four different semi-empirical formulae, namely, the universal decay law (UDL), the Viola-Seaborg (VSS) formula, the modified universal decay law (MUDL), and the modified Brown formula (MBrown), are used to obtain the α-decay half-lives for the considered nuclei. To examine the applicability of relativistic mean-field model within NL3⁎ parametrization, the α-decay energies, and the half-lives of a few known superheavy nuclei within the range 102 ≤ Z ≤ 118 are calculated and the results are compared with the experimental data along with the theoretical predictions. The α-decay energies (Q-values) are estimated from the binding energies of the parent, and daughter from the RMF (NL3⁎) parameter set. The calculated results are compared with macroscopic-microscopic Finite-Range-Droplet-Model (FRDM), Global Nuclear Mass Model (WS3, WS4), Weizsacker-Skyrme mass model (WS⁎) predictions, and the experimental data, wherever available. The possible standard deviations are also estimated for experimental and various theoretical predictions. We find a good consistency for the experimental-to-UDL, FRDM-to-UDL, and WS4-to-UDL estimates of the decay energy and corresponding half-life. The present analysis provides the theoretical predictions within the microscopic model for the upcoming experiments on the superheavy region.

Structural and decay properties of Z = 124 isotopes using RMF densities

We investigate various ground state characteristics of Z = 124 super-heavy nuclei in the region 296 ⩽ A ⩽322 using the relativistic mean field (RMF) formalism with NL3∗ parametrization. First, the calculation was carried out for the binding energy per nucleon, root-mean-square charge (rms) radii, quadrupole deformation parameter, two-neutron separation energies and other observables.The outcomes are comparable to the macro–microscopic predictions made by the Finite Range Droplet Model (FRDM) and the Weizsȧcker-Skyrme (WS) mass model. The binding energies of the parent and daughter nuclei are used to estimate the α-decay energies. Then, the Viola-Seaborg (VSS) formula and the universal decay law (UDL) have been used to explore the α-decay half-lives of two isotopes 124304,305, and the comparison is made with FRDM and WS predictions. The maximum half-lives of 124292,297 isotopes indicate the signature of shell closure.

Cluster decay half-lives in trans-tin and transition metal region using RMF theory

In the present work, we have studied the alpha-like clusters (8Be, 12C, 16O, 20Ne, and 24Mg) decay half-lives in the trans-tin region for (106–116Xe, 108–120Ba, 114–126Ce, and 118–128Nd) and in transition metal region for (156–166Hf, 158–172W, 160–174Os, 166–180Pt, and 170–182Hg) nuclei. These half-lives have been calculated using the shape parametrization model of cluster decay in conjunction with the axially deformed relativistic mean-field model with the NL3* parameter set. They are also compared with the half-lives computed using the latest empirical relations, namely universal decay law and the scaling law was given by Horoi et al. It has been observed that in the trans-tin region the minimum cluster decay half-lives are found at nearly doubly magic or doubly magic daughter 100Sn nucleus (N d = 50, N d is the neutron number of the daughter nucleus) and in transition metal region at N d = 82, which is a magic number. The Geiger–Nuttal plots of half-lives showing Q dependence for different alpha-like clusters from various cluster radioactive emitters are found to vary linearly.

Proton radioactivity and α-decay of neutron-deficient nuclei

Proton radioactivity and α-decay half-lives of neutron-deficient nuclei have been systematically studied. The proton-nucleus interaction potential is developed by single folding the density distribution of the daughter nuclei with the effective M3Y-Paris nucleon-nucleon (NN) interaction. The penetrability is calculated with the Wentzel-Kramers-Brillouin approximation. The applicability of the universal decay law on the proton decay half-lives has been examined and a new set of parameters has been identified. The competition between α-decay and proton radioactivity of neutron-deficient nuclei has been investigated. The proton radioactivity is found to be the dominant mode of decay for nuclides located very close to the proton drip-line. The effect of using different microscopic proton and neutron density distributions on the half-lives for these two decay modes is studied. It is found that the calculated half-lives with the microscopic densities that obtained from the self-consistent Hartree–Fock-Bogoliubov method successfully reproduce the experimental data. The impact of nuclear deformation on the half-lives is investigated for these two decay modes. The influence of nonlocality through the finite-range exchange part of the NN interaction on the α-decay process is elucidated. Our theoretical calculations have been confirmed experimentally and satisfactory agreement has been achieved.

Theoretical calculations of the nuclear deformation effects on α-decay half-lives for heavy and super-heavy nuclei

α-decay half-lives of heavy and super-heavy even–even nuclei, in the range of Z = 80–118, were studied using an improved generalized liquid drop model, in which the deformation effects of both the parent and daughter nuclei are considered. The calculated values reflect a better accuracy of the agreement when compared with the experimental data of known nuclei from Hg to Og. The corresponding standard deviation reduced to 0.3670, which proves that the employed method is reliable to reproduce the α-decay half-lives. Semi-empirical formulas like the Royer formula and the universal decay law were also used for systematic calculations of α-decay half-lives. Based on a detailed analysis of the deformation effects in heavy and super-heavy nuclear regions, it was found that the nuclear deformation has a stronger influence on the super-heavy region. The competition between α-decay and spontaneous fission (SF) was also studied and it was observed that for some isotopes from Pu to Fl, the competition between two decay modes is intense, which reflects that these nuclei may follow both decay modes. A neutron magic number, N = 184, and sub-magic numbers, N = 152 and 162 were observed after the analysis of the α-decay half-lives and the SF half-lives of unknown even–even nuclei.