THEORETICAL STUDY OF DECAY RATES OF NEWLY SYNTHESIZED SUPER HEAVY ELEMENT (original) (raw)
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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 decay half-lives of superheavy nuclei in the WKB approximation
Nucleus, 2011
Alpha decay half-lives of superheavy nuclei are obtained in the context of barrier penetration theory built with the use of Coulomb and proximity potentials, taking into account the quadrupole deformations of nuclei. It is estimated from a classical viewpoint, a possible maximum value of the angular momentum of alpha particles emitted from odd and odd-odd nuclei. Masses and deformations of nuclei are obtained from the macro-microscopic method, with the use of the twocenter shell model. Alpha-decay half-lives are compared with recent experimental results. Se obtienen períodos de semidesintegración alfa en el marco de la teoría de penetración de barrera, esta última construida con el uso de los potenciales de proximidad y de Coulomb, teniendo en cuenta la deformación cuadrupolar de los núcleos. Se estima, desde el punto de vista clásico, el máximo valor posible del momento angular de las partículas alfa emitidas por núcleos impares e impar-impar. Las masas y las deformaciones de los núcleos se obtienen según el método macromicroscópico, con el uso del modelo de capas de dos centros. Los períodos de semidesintegración alfa se comparan con resultados experimentales.
Theoretical studies on the modes of decay of superheavy nuclei
Physical Review C, 2016
The decay modes of recently synthesized superheavy nuclei are investigated by comparing the α-decay half-lives with the spontaneous fission half-lives. α-decay half-lives are calculated using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The agreement between theoretical and experimental α half-lives shows the predictability of the CPPMDN in the superheavy region. A modified formula is proposed for calculating the spontaneous fission half-lives including the shell correction. The agreement between theoretical predictions and experimental results of spontaneous fission half-lives is satisfactory for heavy and superheavy nuclei ranging from Th to Fl. A comparison between the spontaneous fission half-lives computed using eight different formalisms is performed for even-even superheavy nuclei in the range of 108 Z 120. Even though all these models can reproduce the experimental spontaneous fission half-lives, model-to-model variations in predicting the fission half-lives in superheavy region is evident from the study.
On the formation and alpha decay of superheavy elements
Nucl. Phys. A 699 479, 2002
The potential energy governing the entrance and α-decay channels for superheavy elements has been determined within a Generalized Liquid Drop Model including the proximity effects, the asymmetry, an accurate nuclear radius, an adjustment to reproduce the experimental Q value and within the asymmetric two-center shell model and the Strutinsky method. In cold fusion paths doublehump fusion barriers stand and incomplete fusion events may occur. Warm fusion reactions lead to one hump potential barriers and to very excited systems cooling down by neutron or even α-particle evaporation. α-decay half-lives of superheavy elements have been calculated and compared with the new available experimental data.
International Journal of Modern Physics E, 2016
A systematic study on the alpha decay half-lives of various isotopes of superheavy element (SHE) [Formula: see text] within the range [Formula: see text] is presented for the first time using Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated [Formula: see text] decay half-lives of the isotopes within our formalism match well with the values computed using Viola–Seaborg systematic, Universal curve of Poenaru et al., and the analytical formula of Royer. In our study by comparing the [Formula: see text] decay half-lives with the spontaneous fission half-lives, we have predicted [Formula: see text] chain from [Formula: see text]121, [Formula: see text] chain from [Formula: see text]121 and [Formula: see text] chain from [Formula: see text]121. Clearly our study shows that the isotopes of SHE [Formula: see text] within the mass range [Formula: see text] will survive fission and can be synthesized and detected in the laboratory via alpha decay. We hope tha...
Physical Review C, 2013
The radius of a nucleus is one of the important quantities in nuclear physics. Although there are many researches on ground-state properties of superheavy nuclei, researches on charge radii of superheavy nuclei are rare. In this article, nuclear root-mean-square (rms) charge radii of heavy and superheavy nuclei are extracted from the experimental α-decay data. α-decay calculations are performed within the generalized density-dependent cluster model, where α-decay half-lives are evaluated using quasibound state wave functions. The charge distribution of daughter nuclei is determined in the double-folding model to reproduce the experimental α-decay half-lives. The rms charge radius is then calculated using the resulting charge distribution. In addition, a simple formula is also proposed to calculate nuclear charge radii with the experimental α-decay energies and half-lives. The formula is directly derived from the Wentzel-Kramers-Brillouin barrier penetration probability with some approximations. The two different methods show good agreement with the experimental data for even-even nuclei, and the deduced results are consistent with other theoretical models. Moreover, nuclear radii of heavy and superheavy nuclei with Z = 98-116 are extracted from the α-decay data, for which α decay is a unique tool to probe nuclear sizes at present. This is the first result on nuclear charge radii of superheavy nuclei based on the experimental α-decay data.
Physical Review C, 2007
Theoretical α-decay half-lives of the heaviest odd-Z nuclei are calculated using the experimental Qα value. The barriers in the quasi-molecular shape path is determined within a Generalized Liquid Drop Model (GLDM) and the WKB approximation is used. The results are compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulae. The calculations provide consistent estimates for the half-lives of the α decay chains of these superheavy elements. The experimental data stand between the GLDM calculations and VSS ones in the most time. Predictions are provided for the α decay half-lives of other superheavy nuclei within the GLDM and VSS approaches using the extrapolated Audi's recent Qα, which may be used for future experimental assignment and identification.
Analytic expressions for alpha-decay half-lives and potential barriers
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.
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.