Versions Of Proximity Potentials Research Articles

Theoretical study of superheavy elements 294,297Og using different versions of proximity potential

Formation of superheavy nuclei 294,297Og is studied via calculation of evaporation residue cross section. We investigated the influence of nuclear potential on the evaporation residue cross section using nine versions of proximity potential as Prox77, Prox88, BW91, Bass73, Bass77, Denisov, CW76, GP77 and Guo2013. Calculations are performed for 65 projectile-target combinations with convenient half lives. It is found that the combinations 46Ca+248Cf and 48Ca+249Cf are most favorable for the synthesis of the elements 294,297Og with evaporation cross sections 1395 and 279 fb for the 3n channel in proximity potential Guo2013. The lowest value of evaporation cross section is obtained for Bass73 potential. We have also examined the agreement of the results obtained from different potentials with the experimental data for the systems 48Ca+245Cm, 48Ca+248Cm, and 48Ca+249Bk. The results obtained from potentials Guo2013, GP77 and CW76 show better agreement with the experimental results in comparison with other potentials.

Theoretical study on the favored alpha-decay half-lives of deformed nuclei

A systematic study on the α-decay half-lives of nuclei in the range is performed by employing various versions of proximity potentials. To obtain more reliable results, deformation terms are included up to hexadecapole ( ) in the spherical-deformed nuclear and Coulomb interaction potentials. First, the favored α-decay processes in this region are categorized as even-even, odd A, and odd-odd nuclei. Second, they are grouped into two transitions: ground state to ground state and ground state to isomeric states. Owing to the comparison of their root-mean-square deviations (RMSD's), and have the lowest values and better reproduce experimental data. Moreover, by considering preformation probability within the cluster formation model, the results validate the significant reduction in root-mean-square deviations obtained for different versions of proximity. Hence, the deviation between the calculated and experimental data is detracted.

Proton radioactivity within the generalized liquid drop model with various versions of proximity potentials

In the present work, we systematically investigate the proton radioactivity half-lives of spherical proton emitters adopting a generalized liquid drop model (GLDM) with 16 different proximity potentials, of which the proximity potential Prox.77-13 gives the closest results to the experimental data. Combined with the previous conclusion that the GLDM with proximity potential Prox.77-13 can also best describe α decay half-lives, which makes the model more uniform and consistent. Further, we use the proximity potential Prox.77-13 in GLDM to predict the proton radioactivity half-lives of 14 spherical proton emitters that are allowed energetically but not yet observed experimentally or specifically quantified. Finally, we research the Geiger−Nuttall law for proton radioactivity. The results reveal that the Geiger−Nuttall law can also be well used to study the proton radioactivity half-lives of isotopes with the same orbital angular momentum l.

Role of nuclear surface tension coefficients in the isotopic dependence of fusion dynamics for neutron-rich colliding nuclei: New parametrization of fusion barriers

A theoretical approach is developed to study systematically the influence of the nuclear surface tension coefficient, γ, of the proximity formalism on the isotopic behavior of the fusion dynamics over a wide range of neutron-rich colliding systems with condition of 1 ≤ N/Z < 1.6 for their compound nuclei. Here six different versions of the surface energy coefficient (γ-PD03, γ-MS67, γ-MS66, γ-MN81-I, γ-MN81-II and γ-MN76) in the calculation of the nuclear potential based on the original proximity potential 1977are employed. It is found that the fusion barrier characteristics and fusion cross sections follow a linear isotopic dependence which is sensitive to the change in the nuclear surface tension between the reacting nuclei. The maximum sensitivity of the data to this technical parameter is obtained for the use of the γ-PD03 version. Further, it is shown that the sensitivity of the isotopic behavior of the fusion cross sections to the coefficient γ increases by decreasing the incident energy. After the calculation of fusion barrier heights and positions using the different versions of proximity potentials, we have searched for their parametrization. Firstly, we present a pocket formula for fusion barriers which is directly dependent on both the coefficient γ and the N/Z ratio of the isotopic systems. Our analysis for the studied isotopic systems reveals that the agreement with the empirical data is improved when we consider the dependence of the analytical parameterized formulas on this coefficient. Further, the fusion cross sections obtained by the present pocket formula are in good agreement with the corresponding experimental data. A comparison with other well known parameterized forms in the context of isotopic studies is also made.

Effects of Proximity Potentials on the Cross-Sections of 6,8He + 65Cu Halo Fusion Reactions

The comprehensive theoretical study is performed to determine the best proximity potentials in reproducing 6,8He + 65Cu fusion reactions. Twenty three different versions of proximity potentials that consist of Prox 66, Prox 76, Prox 77, Prox 79, Prox 81-I, Prox 81-II, Prox 81-III, Prox 84, Prox 88, Mod-Prox-88, Prox 95, Prox 2003-I, Prox 2003-II, Prox 2003-III, Prox 2010, BW 91, AW 95, Bass 73, Bass 77, Bass 80, CW 76, Ngo 80, and D are used. The theoretical results are compared with experimental data on 6,8He + 65Cu fusion reactions. The appropriate proximity potentials are determined.

Systematic study of α-decay half-lives of super-heavy nuclei with 106≤Z≤118

The α-decay half-lives of the superheavy nuclei are systematically studied using different versions of proximity potential and a exact method to calculate Coulomb potential between spherical and deformed nuclei in the framework of the double folding model. To reproduce the α-decay half-life, the experimental α-decay energy and Wentzel-Kramers-Brillouin approximation have been used. It is found that the computed values by the Ngô 80 are in good compromise with the experimental half-lives in comparison with other versions. Also, by using this version and within QWS4 for determination α-decay energies for superheavy elements, we had predicted the α-decay half-lives for superheavy nuclei which have not been reported yet. The long half-lives with magnitude about 100 seconds are predicted for the superheavy nuclei which are not in stability islands which indicating remarkable stability in comparison with their neighbors. These results are also in good agreement with the predictions of other semi-empirical formulas.

α-Decay half-lives of even–even nuclei of Pb, Po, Rn and Ra isotopes

In the present work, we intended to study the [Formula: see text]-decay half-lives of the even–even nuclei from [Formula: see text]Po to [Formula: see text]Ra in ground state. We investigated a semi-empirical, one-parameter model based on tunneling through a potential barrier with the centrifugal and overlapping effects. Half-lives of [Formula: see text]-decay of even–even nuclei calculated by using different versions of proximity potentials (gpp77, MCW76 and MB77) are compared to experimental data. Also, the computed half-lives are compared with the Royer formula, Akrawy and Poenaru (AKRE) formula, modify Ren (MRen B) formula and Denisov–Khudenko (DEKH) formula and with the experimental data. The results are in good agreement with the experimental data.

Decay of heavy particles from Z = 125 superheavy nuclei in the region A = 295–325 using different versions of proximity potential

Within the framework of Coulomb and proximity potential model (CPPM), the probable heavy particle decays from various isotopes of superheavy nuclei (SHN), [Formula: see text], within the range [Formula: see text]–[Formula: see text] have been studied using two versions of proximity potential; proximity 1977 and proximity 2000. The decay half lives evaluated using proximity 2000 is observed to be higher than the values obtained using proximity 1977. The effect of surface deformation on the decay half lives is studied using Coulomb and proximity potential for deformed nuclei (CPPMDN). As a result of the inclusion of deformation [Formula: see text], the penetrability of the decays are observed to be increased and accordingly the decay half lives are reduced. The estimated values are compared with other theoretical models, Universal curve (UNIV), Universal Decay law (UDL) and the scaling law of Horoi. The odd–even staggering (OES) effect is observed in the emission of odd mass clusters. An intriguing aspect of the study is the effect of the magicity at [Formula: see text] which is confirmed from the plot of [Formula: see text] against the neutron number of the daughter nuclei. Almost all the predicted half lives are favorable for experimental measurements. The Geiger–Nuttall (GN) plots and the Universal curve have been studied for various cluster emissions from various superheavy isotopes with [Formula: see text]. Finally, the linearity of the GN plot and the Universal curve of the heavy particle emissions very well established the strength of CPPM.

Comparative studies for different proximity potentials applied to sub-barrier fusion reactions

Coulomb barrier heights calculated by using 14 different versions of proximity potentials are studied and applied for experimental data of fusion in terms of a recently proposed energy scaling approach. The results show that the descriptions of proximity potentials 77 and 88 for the barrier heights seem to be closest to the values required by the systematics. On the basis of proximity potential 77, the parameterized formulas of the barrier height and radius are obtained. These formulas can calculate the barrier positions and barrier heights reasonably well within the error, respectively. Thus it provides a simple and direct way to calculate the barrier positions and barrier heights for heavy-ion fusion reactions.

Comparative studies for different proximity potentials applied to α decay

Half-lives of α decay of even-even nuclei calculated by using fourteen different versions of proximity potentials are compared to experimental data. The results show that the results of the generalized proximity potential 1977 are very much in agreement with the experimental data. In comparison with the distributions of nuclear potentials at small distances and the distributions of total potentials above the released energy Q α , it is found that at small distances the distributions of nuclear potentials have large difference and the distributions of total potentials are different among the listed proximity potentials. The different potential distributions affect the penetration probability of α, which is related to the half-life of the α decay for each nucleus. The generalized proximity potential 1977 is also used to calculate the half-lives of α decay of nuclei with odd mass numbers. The results show that the generalized proximity potential 1977 can calculate the half-lives of the α decay of almost all nuclei, which underlines and supports the use of the generalized proximity potential 1977 by Santhosh et al. in the Coulomb and proximity potential model (CPPM) and the Coulomb and proximity potential model for deformed nuclei (CPPMDN).

A new technique to determine fusion barrier heights using proximity potentials

We develop a new technique to calculate fusion barrier heights of any fixed target reaction series. We calculate the barrier heights for the fusion reactions of 119 Sn and 197 Au targets using this technique. This technique is simple and very useful for estimating the fusion barrier heights for those reactions for which empirical values are not available. A formula is derived by performing theoretical calculations using different versions of proximity potential. Using this formula, we can predict the barrier height for the fusion reaction of any projectile with 119 Sn or 197 Au target using the empirical barrier height for the fusion reaction of same projectile with 62 Ni target. In order to check the accuracy of this technique, the fusion parameters calculated by this new technique are compared with the fusion parameters calculated by using parameterized formulae presented in a systematic study conducted by using double folding model. the colliding nuclei. The separation between the two col- liding nuclei is related to the internuclear distance between the centers of the colliding nuclei through their nuclear radii. So we need accurate knowledge of nuclear radii. In the present study, we propose a new technique, which can be used to calculate the fusion barrier heights of any fixed target reaction series. For this study, we first compute barrier heights for X + 62 Ni, X + 119 Sn and X + 197 Au reaction series using different versions of proximity potential. Here, X projectile varies from 1 Ht o 59 Co. This study is carried out using proximity potentials PROX 77, PROX 88, PROX 2000, PROX 2000DP, PROX 2010 and MOD-PROX 88.

Proximity Approach to Study the Fusion Barriers for Proton and Helium Induced Reactions

By using various proximity potentials, the fusion barrier heights and positions are calculated for proton and helium induced reactions with targets in the mass range 51 ≤ A ≤ 130 and 12 ≤ A ≤ 233, respectively. The calculated fusion barriers are parameterized by using the relations RBPar = aX1 + b and VBPar = cX2, where X1 and X2 are A21/3 and , respectively. The values of the constants a, b and c are different for different versions of proximity potentials. We and that the parameterized forms derived by using Proximity 1977 yield values closer to the empirical data in proton as well as helium induced reactions and can be used further to estimate directly the barrier parameters for the fusion reactions of proton and helium with any target.

Cluster radioactivity using various versions of nuclear proximity potentials

The systematic study of doubly closed shell ${}^{208}\mathrm{Pb}$-daughter cluster radioactivity using different versions of proximity potentials within the preformed cluster-decay model is extended to daughter nuclei other than ${}^{208}\mathrm{Pb}$. The nuclear proximity potentials used in the calculation of total interaction potential cover a wide range of barrier characteristics. The decay half-life of the cluster changes significantly with the use of these different potentials because of the corresponding change in the preformation probability (${P}_{0}$) and penetration probability ($P$) of the cluster. The cluster radioactivity is worked out at touching as well as at an elongated neck configuration by taking the neck-length parameter $\ensuremath{\Delta}R=0.5$ fm. In order to observe the effect of deformation, the spherical fragmentation of clusters is also taken into account and the standard root-mean-square (rms) deviation is also compared for the various nuclear proximity potentials. It is observed that Prox 1977 reproduces the experimental half-lives very well at $\ensuremath{\Delta}R=0.5$ fm and further improves upon the value obtained in previous work. Thus Prox 1977 turns out to be a better option for studying the cluster decay of radioactive nuclei; however, the calculated half-lives of ${}^{14}\mathrm{C}$ clusters are still poor. With the use of mod-Prox 1988, having stronger isospin and asymmetry dependence, the comparison for ${}^{14}\mathrm{C}$ clusters improves significantly and the standard rms deviation from experimental half-lives comes out to be 1.01 and 1.46 for spherical and deformed choices of fragmentation, respectively. The standard rms deviation reported for various proximity potentials can be further improved if the precise experimental half-lives of 15, out of the 45 clusters used in present study, are made available. Till now only lower limits are available for these clusters. The barrier characteristics of various interaction potentials obtained using different nuclear proximity potentials are also explored in the context of ground-state cluster radioactivity. The new cases of ${}^{34}\mathrm{Si}$ decay of ${}^{238}\mathrm{U}$ and ${}^{14}\mathrm{C}$ and ${}^{15}\mathrm{N}$ decays of ${}^{223}\mathrm{Ac}$ are also included in the present study of 45 clusters. Predictions of half-lives of possible cluster decays in the trans-lead region are also made using Prox 1977. The deformation effect is included with optimum cold orientations.

Analytical parametrization of fusion barriers using proximity potentials

Using the three versions of proximity potentials, namely proximity 1977, proximity 1988, and proximity 2000, we present a pocket formula for fusion barrier heights and positions. This was achieved by analyzing as many as 400 reactions with mass between 15 and 296. Our parametrized formula can reproduced the exact barrier heights and positions within an accuracy of $\pm1%$. A comparison with the experimental data is also in good agreement.