On the formation and alpha decay of superheavy elements (original) (raw)
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Entrance channels and alpha decay half-lives of the heaviest elements
Nuclear Physics A, 2004
The barriers standing against the formation of superheavy elements and their consecutive α decay have been determined in the quasimolecular shape path within a Generalized Liquid Drop Model including the proximity effects between nucleons in a neck, the mass and charge asymmetry, a precise nuclear radius and the shell effects given by the Droplet Model. For moderately asymmetric reactions doublehump potential barriers stand and fast fission of compact shapes in the outer well is possible. Very asymmetric reactions lead to one hump barriers which can be passed only with a high energy relatively to the superheavy element energy. Then, only the emission of several neutrons or an α particle can allow to reach an eventual ground state. For almost symmetric heavy-ion reactions, there is no more external well and the inner barrier is higher than the outer one. Predictions for partial α decay half-lives are given.
International Journal of Modern Physics E
The α decay potential barriers are determined in the cluster-like shape path within a generalized liquid drop model including the proximity effects between the α particle and the daughter nucleus and adjusted to reproduce the experimental Qα. The α emission half-lives are determined within the WKB penetration probability. Calculations using previously proposed formulae depending only on the mass and charge of the alpha emitter and Qα are also compared with new experimental alpha-decay half-lives. The agreement allows to provide predictions for the α decay half-lives of other still unknown superheavy nuclei using the Qα determined from the 2003 atomic mass evaluation of Audi, Wapstra and Thibault.
Alpha and cluster decays of superheavy elements and 2p radioactivity of medium nuclei
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.
Α -Decay Half-Lives of Superheavy Nuclei from a Modified Generalized Liquid-Drop Model
Physical Review C
The α-decay half-lives of superheavy nuclei are studied using the generalized liquid-drop model (GLDM) with 1977 nuclear proximity potential proposed by Blocki et al. [Ann. Phys. (NY) 105, 427 (1977)]. The result obtained with the present formalism is compared with the experimental half-lives and half-lives using GLDM. The standard deviation of the present approach is found to be 0.34, which is less than that of GLDM of Royer (0.56). The study is extended to predict the α half-lives of some of the unknown isotopes in superheavy region. We hope that the predictions on the α-decay half-lives using the present formalism may be helpful in future investigations in this field.
Alpha Decay of Superheavy Nuclei
Arxiv preprint arXiv:1102.2803, 2011
Recently synthesis of superheavy nuclei has been achieved in hot fusion reactions. A systematic theoretical calculation of alpha decay half-lives in this region of the periodic system, may be useful in the identification of new nuclei in these type of reactions. Alpha decay half-lives are ...
Fusion reactions and synthesis of some superheavy nuclei
NPA 1000 (2020)121811, 2020
The potential barriers standing against the formation of some superheavy nuclei have been studied within a Generalized Liquid Drop Model taking into account the proximity forces acting between surfaces in regard, the charge and mass asymmetry, the shell and pairing effects and an adjustment to reproduce the experimental or predicted Q value. Quasimolecular shapes leading from two spheres to one sphere have been used. In very asymmetric entrance channels one hump potential barrier stands and might lead to very excited nuclei cooling by neutron or α particle evaporation. For less asymmetric reactions double hump potential barriers appear and quasifission or alpha decay of compact and creviced one-body shapes may occur in the external well beside fusion-fission events in the first inner well. For almost symmetric reactions there is no more external barrier but rather a continuous climb till the sphere. Predictions of alpha decay half-lives of the studied superheavy nuclei are given using a recently proposed formula.
Half-life predictions for decay modes of superheavy nuclei
Journal of Physics G: Nuclear and Particle Physics, 2004
We applied the Effective Liquid Drop Model (ELDM) to predict the alpha-decay, cluster emission and cold fission half-life-values of nuclei in the region of Superheavy Elements (SHE). The present calculations have been made in the region of the ZN-plane defined by 155 < N < 220 and 110 < Z < 135. Shell effects are included via the Q-value of the corresponding decay case. We report the results of a systematic calculation of the half-life for the three nuclear decay modes in a region of the ZN-plane where superheavy elements are expected to be found. Results have shown that, among the decay modes investigated here, the alpha decay is the dominant one, i. e. the decay mode of smallest half-lives. Half-life predictions for alpha decay, cluster emission and cold fission for the isotopic family of the most recent SHE detected of Z=115 and for the isotopic family of the already consolidated SHE of Z=lll are presented.
Alpha Decay Favoured Isotopes of Some Superheavy Nuclei: Spontaneous Fission Versus Alpha Decay
2012
Spontaneous fission and alpha decay are the main decay modes for superheavy nuclei. The superheavy nuclei which have small alpha decay half-life compared to spontaneous fission half-life will survive fission and can be detected in the laboratory through alpha decay. We have studied the alpha decay half-life and spontaneous half-life of some superheavy elements in the atomic range Z = 100-130. Spontaneous fission half-lives of superheavy nuclei have been calculated using the phenomenological formula and the alpha decay half-lives using Viola-Seaborg-Sobiczewski formula (Sobiczewski et al. 1989), semi empirical relation of Brown (1992) and formula based on generalized liquid drop model proposed by Dasgupta-Schubert and Reyes (2007 ). The results are reported here.
On the nuclear structure and stability of heavy and superheavy elements
Nuclear Physics A, 1969
Nuclear potential energy surfo:>,ces a~ a functlcin of cleforma:tions are calculated on the basis of a nt)dified osclll.at.or model. In particular, quadrupole (P 2) and hexadecupole (P 1) deformation;; nrc • considered. The average behavior of the sur_face is norrr:a.lized to that ofu liquid drop through 'the employment of a gei1eraliz.ed Strutinski prescription. In this way a synthesi:; of the slnglc particle model and the liquid drop model is obtained. Lowest minima. in the potential energy surfaces give the ~rounc~ state masses ond distortions. These results compare extremely well wi.th experimental data. Spontaneous fission half lives are obtained. 'l'he inertial parameters as::wcia ted with fission barrier pcnetn:ttlon are derived empidcally as well as by a microscopic modeL Sh::tpe (fisslon) isomeric states _o.re also found. Thelr N and Z dependence in the present model are discusccd and results tabulated. The calculations arc extended to the predicted nuperbea.vy region around Z :: 111~ nnd N == 18/1. 1'he total overall stnh:U.i ty ~rith respect to alpha L-tnd beta. decay, and Epontaneous fission fs fou .. "ld to be most favorable in the vic:!n.Uy of b:::: 110 and N = J.8IL Detailed diagrams and tables arc exhibited.