Nuclear Proximity Potential Research Articles

Exploring asymmetric fission in 180Hg⁎ compound nucleus using dynamical cluster-decay model

The observed asymmetric fission of the 180Hg⁎ compound nucleus challenges conventional expectations of symmetric fission, which are attributed to the presence of shell closures at Z=40 (semi-magic) and N=50 (magic). To comprehend this novel phenomenon, the dynamical cluster-decay model has been employed. For the first time, this model incorporates the bulk and neutron-proton asymmetry coefficients of the nuclear shape-dependent mass excess formula which are tuned recently to the ground state mass excess data of AME2020 and/or FRDM(2012) along with the temperature dependence for the nuclear shape and the surface energy coefficient of the nuclear proximity potential. The calculations have considered nuclear shapes as both spherical and deformed (quadrupole), with and without temperature dependence for the quadrupole deformation. A new minimum appears in the symmetric mass region of the fragmentation potential for masses (80, 100), when the fragments are deformed and optimally oriented, at an energy lower than that obtained for masses (90, 90) where the fragments are assumed to be spherical or nearly spherical at higher temperatures. This new minimum seems equivalent to the appearance of a new shell gap with deformation and is responsible for the asymmetric fission of 180Hg⁎. The most probable fission channel and the transition from asymmetric to symmetric mass distribution at higher excitation energies are consistent with experiments for the current temperature dependence assigned to the quadrupole deformation parameter.

Investigating the impact of the universal function of the nuclear proximity potential in heavy-ion fusion cross sections

The fusion barriers and cross sections of 15 colliding systems with 320 ≤ Z 1 Z 2 ≤ 1512 are investigated in detail to understand the influence of the universal function of proximity potential formalism in the heavy-ion fusion mechanism. To realize this goal, we select three versions of the phenomenological proximity potentials, including Prox. 77, Zhang 2013, and Guo 2013, to calculate the nucleus–nucleus potential. The experimental fusion cross sections for the selected reactions are analyzed using the standard coupled-channel calculations, including couplings to the low-lying 2+ and 3− states in the target and projectile. The calculated results show that the universal functions of the Guo 2013 and Prox. 77 models provide the lowest and highest fusion barriers, respectively. In addition, it is found that the height of the fusion barriers is enhanced by increasing the mass number of the projectile from light to heavy ones. The highest sensitivity to the mass number of the projectile belongs to the results of Prox. 77. A discussion is also presented on the influence of the universal function on the radial behavior of the interaction potential in the allowed region for overlapping configurations. Our results reveal that the best fit to the experimental data of the fusion cross sections for the reactions involving light and medium nuclei is obtained using the universal function of the Zhang 2013 model. For the heavier systems, the results of the Guo 2013 model at sub-barrier energies provide a good description of the available data.

The study of angular momentum on the fusion of [formula omitted]Si+[formula omitted]Si, using SEDF in semiclassical extended Thomas-Fermi approach

The total fusion cross-sections are calculated for energies both above and below the potential barrier by using the properties of the interaction potential in Hill-Wheeler approximation for a positive Q-value system 1428Si+1428Si. The Coulomb and centrifugal parts of the potentials are added directly to the nuclear proximity potential to calculate the total interaction potential, where nuclear proximity potential is obtained in semiclassical extended Thomas-Fermi approach of Skyrme energy density formalism for Skyrme SIV parametrization. The angular momentum spectrum of total cross sections is obtained and calculated by using angular momentum dependent properties of the total interaction potential. The properties of total interaction potential, which are usually treated as independent of angular momentum, i.e. barrier height, barrier position and its width are calculated and found to depend sharply on the angular momentum value at a fixed center of mass energy. It effect the fusion cross-section sufficiently above the barrier energy. However at energies below the barrier energy the addition of large angular momentum values have negligible effects on fusion cross-section. Further, the maximum in fusion cross-section is observed at a particular value of angular momentum, which is not equal to the maximum value of angular momentum.

Theoretical calculation of alpha decay half-lives of Neptunium nuclei using modified generalized liquid drop model

We considered the α-decay half-lives of neptunium (ZNp = 93) nuclei in the case of deformed nuclei in the range 219 ≤ A ≤ 239 using the generalized liquid-drop model (GLDM) with 1977 nuclear proximity potential suggested by Blocki et al. (1977) [29]. Also, we analyzed the α-decay half-lives of Np isotopes within the WKB method and the Deformed Proximity Potential Model (DPPM). We consider the quadrupole and hexadecapole deformations at θ=0, θ=30, θ=45, and θ=90 degrees. The calculated half-lives and the alpha decay branching ratios are compared with experimental data and are in good agreement. We compared the results obtained with the corresponding experimental data and with the models UNIV, UDL, SemFIS, the Coulomb and Proximity Potential Model (CPPM), SLB and Royer and it is found that they match well over a wide range. The calculated results are in reasonable agreement with the experimental data. Therefore, DPPM gives reliable and accurate results for favored α-decays in the neptunium mass region.

Impact of noncoplanar degrees of freedom on quasifission contributions with the estimation of unobserved decay channels for the study of Pt*196 using the dynamical cluster-decay model

In Phys. Rev. C 98, 041603 (2018) it was demonstrated that the noncoplanar degrees of freedom (or azimuthal angle ${\mathrm{\ensuremath{\Phi}}}_{c}\ensuremath{\ne}{0}^{0}$), including higher-multipole deformations ${\ensuremath{\beta}}_{\ensuremath{\lambda}i}$ ($\ensuremath{\lambda}=2,3,4;\phantom{\rule{4pt}{0ex}}i=1,2$), and the compact orientations ${\ensuremath{\theta}}_{ci}$ are the most essential set of parameters in the dynamical cluster-decay model (DCM), in order to study heavy-ion reactions. In this work, we study the comparison between the coplanar ($\mathrm{\ensuremath{\Phi}}={0}^{\ensuremath{\circ}}$) and noncoplanar (${\mathrm{\ensuremath{\Phi}}}_{c}\ensuremath{\ne}{0}^{\ensuremath{\circ}}$) configurations, including higher multipole deformations, for $^{196}\mathrm{Pt}^{*}$ formed via the $^{132}\mathrm{Sn}+^{64}\mathrm{Ni}$ reaction. This reaction was earlier studied [M. K. Sharma et al., J. Phys. G: Nucl. Part. Phys. 38, 055104 (2011)] by one of our collaborators but only with $\mathrm{\ensuremath{\Phi}}={0}^{\ensuremath{\circ}}$, including quadrupole deformations, ${\ensuremath{\beta}}_{2i}$ alone having ``optimum'' orientations (${\ensuremath{\theta}}_{\mathrm{opt}.}$), with the result of noncompound nucleus [nCN, equivalently quasi-fission (qf)] contribution at higher energies. The only parameter of the DCM is the neck length $\mathrm{\ensuremath{\Delta}}R$, whose value for the nuclear proximity potential used here remains within its range of validity ($\ensuremath{\approx}2$ fm). The evaporation residues (ERs) and fission cross section (${\ensuremath{\sigma}}_{ff}$) are calculated in reference to available experimental data at near- and sub-barrier energies for $^{196}\mathrm{Pt}^{*}$. As a result of inclusion of ${\mathrm{\ensuremath{\Phi}}}_{c}\ensuremath{\ne}{0}^{\ensuremath{\circ}}$, the nCN contribution approaches zero at higher energies and corresponds to ${P}_{\mathrm{CN}}=1$, which is rather significant for the $\mathrm{\ensuremath{\Phi}}={0}^{\ensuremath{\circ}}$ configuration. Secondly, in this attempt we have tried to explore the evolution of the neck-length parameter ($\mathrm{\ensuremath{\Delta}}R$), which will help us to estimate the cross sections of unobserved decay channels.

A systematic study of alpha decay in actinide nuclei using modified generalized liquid drop model

The alpha decay half-lives of actinides within modified generalized liquid drop model (MGLDM) are investigated by the Wentzel–Kramers–Brillouin (WKB) barrier penetration probability. The potential barrier was studied taking in to account of nuclear proximity, coulomb interaction and centrifugal potential with the inclusion of angular momentum. This work predicts the alpha decay half-lives of unknown actinide nuclei such as [Formula: see text]Am, [Formula: see text]Cm, [Formula: see text]Bk, [Formula: see text]Es and [Formula: see text]No. The calculated alpha decay half-lives reproduce accurately the experimental data. The predictions provided for the alpha decay half-lives within the MGLDM may be helpful for identifying the new isotopes in this field.

Study of the surface energy coefficient used in nuclear proximity potential from density-dependent nucleon–nucleon interactions

The nuclear surface tension coefficient, γ, of the proximity potential is systematically investigated from the microscopic double-folding (DF) model accompanied by the realistic density-dependent nucleon–nucleon (NN) interactions. In the present work, we select six versions of density-dependent M3Y–Paris effective NN forces, including DDM3Y1 (with K=176MeV), CDM3Y1 (with K=188MeV), CDM3Y3 (with K=217MeV), CDM3Y5 (with K=241 MeV), CDM3Y6 (with K=252MeV) and BDM3Y1 (with K=270MeV). A total of 70 heavy-ion fusion reactions with condition 48≤Z1Z2≤2460 for the charge product of their reacting nuclei have been analyzed. By fitting the calculated values against the asymmetry parameter As, we present a new analytical formula for the parameter γ which is directly dependent on the nuclear matter (NM) incompressibility constant K. It is shown that the presently obtained formula in proximity potential model can reproduce the fusion data well. In this study, a discussion is also presented about the influence of the incompressibility constant K on the interaction potentials and also on the fusion cross sections resulting from the proximity approach for different heavy-ion reactions.

Quaternary fission in Cf244–254 isotopes with two α particles as middle fragments

The quaternary fission of $^{244--254}\mathrm{Cf}$ isotope with two $\ensuremath{\alpha}$ particles as the middle fragments in collinear configuration has been studied by taking the interacting barrier as the sum of Coulomb and nuclear proximity potential. The most favorable quaternary fission path is the one that has a high Q value and a minimum driving potential with respect to the mass and charge asymmetries. The favorable fragment combinations are obtained from the cold reaction valley plot and then calculating the yield for charge minimized fragments. For $^{244,248,254}\mathrm{Cf}$ isotopes, the highest yield is predicted for the isotope of Sb as one fragment, $^{134}\mathrm{Sb}$ ($Z=51$, $N=83$), $^{130}\mathrm{Sb}$ ($Z=51$, $N=79$), $^{132}\mathrm{Sb}$ ($Z=51$, $N=81$), respectively, whereas for $^{246}\mathrm{Cf}$ isotope, fragments with isotope of I as one fragment $^{134}\mathrm{I}$ ($Z=53$, $N=81$) possesses the highest yield. For $^{250}\mathrm{Cf}$ isotope, fragments with isotope of In as one fragment, $^{132}\mathrm{In}$ ($Z=49$, $N=83$) possesses the highest yield. In the case of $^{252}\mathrm{Cf}$ isotope, the highest yield is for the fragments with Te as one fragment, $^{132}\mathrm{Te}$ ($Z=52$, $N=80$). These findings confirm the role of doubly magic or near doubly magic nucleus in quaternary fission, which supports the conclusion by Poenaru et al. [Nucl. Phys. A 747, 182 (2005)]. The deformation and orientation of fragments has also been taken into account for the two $\ensuremath{\alpha}$ accompanied quaternary fission, and it has been found that in addition to closed shell effect, ground-state deformation also plays an important role in determining the isotopic yield in the quaternary fission process. We hope that our study on isotopic yield in quaternary fission of even-even $^{244--254}\mathrm{Cf}$ isotope will be a guide for future experiments.

Süper-ağır çekirdeklerin kendiliğinden fisyon yarı ömürlerinin farklı modellerdeki hesaplamaları

The spontaneous fission (SF) is a key decay energetically feasible for heavy and superheavy nuclei (Z≥90) and it is an important limiting factor which describes the stability of synthesized superheavy nuclei. Since the fission decay is complex, it is difficult to explain such a multi-dimensional system in a complete microscopic manner. In this study, SF half-lives of 284Cn and 284Fl superheavy nuclei are investigated using the direct method, the Universal Decay Law (UDL). The fission decay constant for each possible case is computed by using the UDL and then the SF half-life for 284Cn and 284Fl superheavy nuclei are predicted. The calculated SF half-lives are compared with the results of other semi-empirical formulas as well as experimental data. Furthermore, the results are compared with ones of the model in which they proposed this direct method for the SF by using nuclear proximity and Coulomb potentials. Good agreement is achieved between the results of this approach and the others. This study shows that UDL would also be used in the half-lives calculations of Spontaneous Fission of superheavy nuclei in a direct way.

Comparative study for different nuclear proximity potentials applied to quasi-elastic scattering and fusion reactions

Within the framework of the empirical barrier distribution model (EBDM), we attempt to extend our previous study (R. Gharaei et al. (2018) [22]) for analyzing systematically the heavy-ion fusion and quasi-elastic scattering reactions using fourteen different versions of the proximity potentials. The main objective of the present study is to study the performance of various nuclear proximity potentials in reproducing the fusion cross sections and quasi-elastic cross sections simultaneously. Our finding reveals that the EBDM approach with proximity potential 1977 (Prox. 77) and modified proximity potential 1977 (Mod. Prox. 77) generate best estimates of the fusion and quasi-elastic scattering cross sections data. Further, the obtained results for the presently studied reactions show that the different proximity potentials provide a more accurate description for the experimental data of the fusion excitation functions in comparison with the large-angle quasi-elastic scattering excitation functions.

Study of the surface energy coefficient used in nuclear proximity potential of the $ \alpha$-nuclei systems from density-dependent nucleon-nucleon interactions

An attempt has been made to study systematically the nuclear surface tension coefficient, $ \gamma$ , of the proximity formalism by using the microscopic double-folding (DF) model with the realistic density-dependent (DD) nucleon-nucleon interaction for the ground-state-to-ground-state $ \alpha$ -decays of 235 parent nuclei with $ Z=61\mbox{--}99$ . In the calculations of DF model, the nucleon-nucleon (NN) interactions are formulated using the effective M3Y force of the CDM3Y6 based on the G -matrix elements of the Paris interaction. We present a new dependence of the surface energy coefficient $ \gamma$ on the asymmetry parameter $ A_s$ of the $ \alpha$ -nuclei systems by fitting all of the calculated values. Using the presently obtained formula of the coefficient $ \gamma$ in the proximity potential we calculate the theoretical values of the alpha-decay half-lives for different nuclei in the framework of the Wentzel-Kramers-Brillouin (WKB) approximation. Results of our calculations are compared to the values of the experimental data and proximity potential 1977. Good agreements are found. The quality of the proximity potential accompanied by the analytical formula of the surface energy coefficient is tested for fusion reactions between $ \alpha$ -particles and heavy nuclei 40 Ca, 48 Ti, 51V , 59Co , 63Cu , 93Nb , 154Sm and 162Dy The evaluated $ \alpha$ -capture cross sections agreed well with the corresponding experimental data. In the present study, the role of the proton and neutron magic numbers of daughter nuclei and also the Geiger-Nuttall plots of $ \log_{10} (T_{1/2})$versus$ Q_{\alpha}^{-1/2}$ for various isotopes of heavy parent nuclei have been studied.

Isotopic yield and half-life of spontaneous fission for Cn284 and Fl284 superheavy isobars using direct calculation and semiempirical formulas

Isotopic yields and half-lives of $^{284}\mathrm{Cn}$ and $^{284}\mathrm{Fl}$ superheavy nuclei are calculated using nuclear proximity and Coulomb potentials. The energy released in fission, $Q$ value, driving potential $(V\ensuremath{-}Q)$, the penetrability through barrier, fission decay constant, and relative yield for each possible pair of fission fragments are obtained. According to the fragments mass and charge asymmetry, the most favored binary fragmentation is occurred for the highest $Q$ value and the lowest driving potential. For spontaneous binary fission of $^{284}\mathrm{Cn}$ superheavy nuclei, the higher relative yields are belong to production of $^{128}\mathrm{Sn}$ and $^{134}\mathrm{Te}$ fragments and for $^{284}\mathrm{Fl}$ superheavy isotope, the maximum yield were observed for $^{136}\mathrm{Xe}$ as one of the fission fragments. The comparison between the obtained isotopic relative yield shows the role of magic and near-magic closed-shell fragments in having the highest isotopic yield. Fission decay constant for each possible fragmentation is calculated and then by summation over them, the total decay constant and fission half-life for $^{284}\mathrm{Cn}$ and $^{284}\mathrm{Fl}$ superheavy nuclei are estimated. Finally, the calculated half-lives using direct method are compared with the results of semiempirical formulas as well as experimental data. Satisfactory agreement is achieved between the results of this approach and the experimental data than the results of semiempirical formulas.

Studies on the cold binary fragmentation of even–even 230–250U isotopes

Within the framework of the Coulomb and proximity potential model (CPPM), we studied the cold binary fission of even–even 230–250U isotopes using the two versions of the nuclear proximity potential, Proximity 1977 and Proximity 2000. The most favorable binary fission path is the one that has a high Q value and a minimum driving potential with respect to the mass and charge asymmetries. A nucleus with doubly-closed shell or near doubly-closed shell always appears as the heaviest nucleus in the favored channel of the binary fission of all the mentioned isotopes. For the 230,232,234U isotopes, the highest yield was predicted for the isotope of Pb (Z=82) as one fragment, whereas for the 236U isotope, fragmentation with the isotope of Hg (Z=80) as one fragment possesses the highest yield. For the 238U isotope, fragmentation with the isotope of Pt (Z=78, N=126) as one fragment possesses the highest yield. In the case of the 240,242,244,246,248,250U isotopes, the highest yield is for the fragmentation with Sn (Z=50) as one fragment. It was found that asymmetric splitting is superior for U isotopes with mass number A≤238 and symmetric splitting is superior for U isotopes with A≥240. The computed penetrability and half-lives using the two different proximity potentials for the cold binary fission of 230–250U isotopes were compared with the available experimental data collected from Holden et al. [Pure Appl. Chem. 72 (2000) 1525]. The two results were found to be in agreement with each other. Dans le cadre du modèle CPPM (Coulomb et potentiel de proximité), nous avons étudié la fission froide binaire d'isotopes pairs–pairs 230–250U, en utilisant les deux versions Proximity 1977 et Proximity 2000 du potentiel de proximité nucléaire. La voie la plus favorable pour la fission binaire est celle qui a une valeur de Q élevée et un potentiel d'entraînement minimal par rapport aux asymétries de masse et de charge. Pour tous les isotopes mentionnés, le canal le plus favorable est celui dans lequel le noyau le plus lourd est à couche doublement compléte ou presque doublement compléte. Pour les isotopes 230,232,234U, on prévoit que le rendement le plus élevé est obtenu quand l'un des fragments est un isotope de Pb (Z=82), tandis que, pour l'isotope 236U, la fragmentation qui donne naissance à un isotope du mercure (Z=80) a le meilleur rendement. Pour l'isotope 238U, la fragmentation conduisant à l'isotope de platine (Z=78, N=126) a le rendement le plus élevé. Dans le cas des isotopes 240,242,242,244,244,246,248,250U, le rendement le plus élevé est obtenu quand la fragmentation mène à l'étain (Z=50). Le fractionnement asymétrique est favorisé pour les isotopes de l'uranium avec un nombre de masse A≤238 et le fractionnement symétrique pour les isotopes de l'uranium avec A≥240. La pénétrabilité et les demi-vies calculées à l'aide des deux potentiels de proximité pour la fission froide binaire des isotopes 230–250U ont été comparées aux données expérimentales disponibles, reproduites par Holden et al. (Pure Appl. Chem. 72 (2000) 1525). On a constaté que les deux résultats étaient en bon accord.

Collective clusterization approach to investigate the relevance of deformation effects in Sn radioactivity

The role of deformations and orientations is studied in cluster decays of various radioactive nuclei leading to doubly magic 100Sn or 132Sn daughter nucleus, using the preformed cluster model (PCM). This model treats the cluster emission process via tunnelling across the potential barrier, the cluster/fragment being preformed with a relative probability $ P_0$. With the incorporation of deformation and orientation effects, the fragmentation potential, the penetration path and related barrier characteristics get significantly modified, due to which both the preformation probability $ P_0$ and penetrability P of the emitting cluster get influenced. The calculated half-lives of the decaying clusters calculated using PCM are found to be within the upper limits of the present experiments. The influence of deformations and orientations on Sn radioactivity is also seen in terms of various barrier characteristics such as barrier modification, barrier height, etc. Moreover, the role of different nuclear proximity potentials, i.e., Prox 77, Prox 88 and Prox 00, is analyzed in the context of potential energy surfaces (PES) in the ground-state decay of parent nucleus. The behavior of PES is explored including, as well as without including, the shell corrections in the binding energies, which in turn help to explore the importance of doubly magic closed shell configuration of daughter and cluster nuclei. The possible role of higher order multipole deformations (i.e., up to $ \beta_{4i}$) is also analyzed in view of the fragmentation path and barrier tunnelling characteristics.

Relevance of different Skyrme forces in the dynamics of [formula omitted] reactions

The role of different Skyrme forces and associated neutron transfer effect is investigated in the view of Ca40,48+96Zr reactions. The fusion cross section has been calculated using Wong formula and extended Wong model, wherein neutron transfer effect is studied by scaling the transmission probability of contributing channel(s). The decay analysis is carried out in the framework of dynamical cluster decay model, where the neck length ΔR and corresponding barrier modification ΔVB are used to explore the neutron transfer effect in the decaying fragments. For fusion and subsequent decay, the nuclear proximity potential is calculated using Skyrme interactions such as SIII, GSkI, SkT1, SkT2, and SkT3. In Ca40+96Zr case, the fusion hindrance is observed at sub barrier energies for the use of SIII, SkT1, SkT2 Skyrme forces. The cross sections are improved to some extent for GSkI force. Further, the inclusion of 1n-transfer channel in the calculations shows that the experimental data is adequately addressed for GSkI force, however, the correction of 1n-transfer channel for SkT1 (or SIII, SkT2 forces), persists with the poor fit to experimental data. In the decay analysis, the interaction potentials significantly affect the structural properties of decaying fragments as is clear from the fragmentation potential and preformation probability. Both, the fusion and decay analysis consistently advocate that GSkI force comprising of extended density-dependent term is able to address the sub barrier anomalies. The neutron transfer effect is explored in view of different choices of the Skyrme forces, which shows that the forces with higher barrier lead to more neutron transfer channel effect and vice versa.

Isotopic yield and half-lives for the spontaneous fission of 280Ds and 282Cn, superheavy nuclei

The spontaneous fission of the 280Ds and 282Cn superheavy nuclei has been studied using the isotopic yield method. The Coulomb and the nuclear proximity potentials are considered for the fission barrier. The energy released in fission (Q-values), the driving potential ( $ V-Q$ ), the penetrability, the decay constant and the fission yield for each fragmentation have been calculated. As expected, with respect to the mass and charge asymmetry, the most favorable fragmentation in the binary spontaneous fission occurs for the highest Q-value and consequently for the lowest value of the driving potential. For the spontaneous fission of 280Ds and 282Cn superheavy isotopes, the highest yields have been seen for 134Te $ (N = 82, Z = 52)$ and 136Xe $ (N = 82, Z = 54)$ closed shell magic isotopes, respectively. The role of magic and near magic closed shell fragmentation is indicated by the analysis of the relative yields. The spontaneous fission half-lives of 280Ds and 282Cn have also been obtained and compared with the results of other theoretical and semi-empirical methods as well as experimental data. The comparison has revealed that the results of the present study acceptably agreed with the experimental data than the other theoretical and semi-empirical methods.

Analysis of heavy-ion fusion reactions using new parameterized form of the universal function of nuclear proximity potential

In the present work, we modify the original version of this formalism (Prox. 77) using a new analytical form of the universal function which is formulated based on the double-folding model with three density-dependent versions of the M3Y-type interactions, namely DDM3Y1, CDM3Y3 and BDM3Y1, for 46 fusion systems with condition 48≤Z1Z2≤2460 for charge product of their participant nuclei. It is found that when the Prox. 77 potential is accompanied by each of the formulated universal functions, the agreement between the theoretical and experimental data of the fusion barrier heights increase for our selected systems. The obtained results of this study reveal that the saturation property of cold nuclear matter plays a key role in the calculations of the fusion cross sections. We conclude that the Prox. 77 model with universal function based on the BDM3Y1 interactions provides the best results for fusion barrier heights and cross sections. On the basis of the prox. 77(BDM3Y1) potential model, we present the parameterized formulas for fusion barrier heights VB and positions RB. These formulas can calculate the values of RB andVB with good accuracy in comparison with the experimental data. A comparison is also presented among the theoretical results of the present work and those obtained by the modified form of the original version of proximity approach through the universal function and surface energy coefficients available in the literature.

Cold binary fragmentation of even–even 238–248Pu isotopes

Within the framework of Coulomb and proximity potential model, we studied the cold binary fission of even–even 238–248Pu isotopes using the two versions of nuclear proximity potential, Proximity 1977 and Proximity 2000. The most favorable binary fission path is the one that has a high Q value and a minimum driving potential with respect to the mass and charge asymmetries. A nucleus with doubly closed shell or near doubly closed shell always appears as the heaviest nucleus in the favored channel of the binary fission of all the mentioned isotopes. For 238Pu isotope, the highest yield was predicted for the isotope of Pb (Z = 82) as one fragment, whereas for 240,242Pu isotopes, fragments with isotope of Hg (Z = 80) as one fragment possesses the highest yield. In the case of 244,246,248Pu isotopes, the highest yield is for the fragments with Sn (Z = 50) as one fragment. It was found that asymmetric splitting is superior for Pu isotopes with mass number A ≤ 242 and symmetric splitting is superior for Pu isotopes with A ≥ 244. We computed relative yields for the cold binary fission of even–even 238–248Pu isotopes using two different proximity potentials. These results were compared with the available experimental data collected from the double energy method by Wagemans et al. (Nucl Phys A 502:287c, 1989). The two results were found to be in agreement with each other.

Impact of spin-orbit density dependent potential in heavy ion reactions forming Se nuclei

The Skyrme energy density formalism is employed to explore the effect of spin-orbit interaction potential by considering a two nucleon transfer process via various entrance channels such as 23Na + 49V , 25Mg + 47Ti , 27Al + 45Sc , 29Si + 43Ca and 31P + 41K , all forming the same compound system 72Se $ ^{\ast}$ , using both spherical as well as quadrupole deformed ( $ \beta_{2}$ nuclei. For spherical nuclei, the spin-orbit density part $ V_{J}$ of nuclear potential remains unaffected with the transfer of two nucleons from the target to the projectile, however, show notable variation in magnitude after inclusion of deformation effects. Likewise, deformations play an important role in the spin-orbit density independent part $ V_{P}$ , as the fusion pocket start appears, which otherwise diminish for the spherical nuclei. Further, the effect of an increase in the N/Z ratio of Se is explored on $ V_{J}$ as well as $ V_{P}$ and results are compared with transfer channels. In addition to this, the role of double spin-orbit parameters ( $ W_{0}$ and $ W'_{0}$ with relative contribution of the isoscalar and isovector parts of spin-orbit strength is explored in view of SkI2, SkI3 and SkI4 Skyrme forces. Beside this, the decay path of 72Se $ ^{\ast}$ nucleus formed in 27Al + 45Sc reaction is investigated within the framework of dynamical cluster decay model (DCM), where the nuclear proximity potential is obtained by both Skyrme energy density formalism (SEDF) and proximity pocket formula. The fusion hindrance in the 27Al + 45Sc reaction is also addressed via the barrier lowering parameter $ \Delta V_{B}$ . Finally, the contribution of spin-orbit density dependent interaction potential is estimated for the 27Al + 45Sc reaction using single ( $ W_{0}$ or $ W_{0}'$ and double spin-orbit parameters ( $ W_{0}$ and $ W_{0}'$ .

A study of probable alpha-ternary fission fragments of 257Fm

The probable α-accompanied cold ternary fission fragments of 257Fm are studied using six types of nuclear proximity potentials. We have studied the driving potential, probability, relative yield and half-lives of possible alpha ternary fission fragments. It is clear from present study that the alpha accompanied cold ternary fission reactions of 257Fm having minimum driving potential, maximum fission yield and small fission half lives for 48Ca + 205Pt + 4He. Hence this combination is recognized as most probable alpha ternary fission fragments of 257Fm due to the presence of doubly magic nucleus 48Ca. This study finds important in the experiments on alpha ternary fission of 257Fm.