Alpha decay and nuclear deformation: the case for favoured alpha transitions of even-even emitters*

Garcı́a, F.; Rodriguez, Oscar Maurício Hernandez; Gonçalves, Marco Antônio; Duarte, S. B.; Tavares, O. A. P.; Guzmán, F.

doi:10.1088/0954-3899/26/6/301

Cited by 31 publications

(23 citation statements)

References 38 publications

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“…The experimental alpha decay data are from Refs. [59][60][61][62][63][64][65][66][67][68]. In the case of the Nd isotopes 144 Nd is the only nucleus around the chosen range which has experimental alpha decay data therefore its half life has been included in the graph.…”

Section: Alpha Decay Resultsmentioning

confidence: 99%

Systematic decay studies of even–even 132–138Nd, 144–158Gd, 176–196Hg and 192–198Pb isotopes

Santhosh

Sahadevan

2010

Nuclear Physics A

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The alpha and cluster decay properties of the 132-138 Nd, [144][145][146][147][148][149][150][151][152][153][154][155][156][157][158] Pb eveneven isotopes in the two mass regions A = 130-158 and A = 180-198 are analyzed using the Coulomb and Proximity Potential Model. On examining the clusters at corresponding points in the cold valleys (points with same A 2 ) of the various isotopes of a particular nucleus we find that at certain mass numbers of the parent nuclei, the clusters emitted are getting shifted to the next lower atomic number. It is interesting to see that the change in clusters appears at those isotopes where a change in shape is occurring correspondingly. Such a change of clusters with shape change is studied for the first time in cluster decay. The alpha decay half lives of these nuclei are computed and these are compared with the available experimental alpha decay data. It is seen that the two are in good agreement. On making a comparison of the alpha half lives of the normal deformed and superdeformed nuclei, it can be seen that the normal deformed 132 Nd, [176][177][178][179][180][181][182][183][184][185][186][187][188] Pb nuclei are found to be better alpha emitters than the superdeformed (in excited state) 134,136 Nd,[190][191][192][193][194][195][196] Pb nuclei. The cluster decay studies reveal that as the atomic number of the parent nuclei increases the N = Z cluster emissions become equally or more probable than the N = Z emissions. On the whole the alpha and cluster emissions are more probable from the parents in the heavier mass region (A = 180-198) than from the parents in the lighter mass region (A = 130-158). The effect of quadrupole (β 2 ) and hexadecapole (β 4 ) deformations of parent and fragments on half life times are also studied.

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Section: Alpha Decay Resultsmentioning

confidence: 99%

Systematic decay studies of even–even 132–138Nd, 144–158Gd, 176–196Hg and 192–198Pb isotopes

Santhosh

Sahadevan

2010

Nuclear Physics A

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“…5 A lot of new experimental and theoretical investigation on alpha decay half-life has been developed during the last three years or so. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] An important study about alpha and beta decay for astrophysical and radioactive-ion-beam applications has been undertaken by Möller et al in Ref. 21. Recently, half-life values for spontaneous nuclear decay processes (proton emission, alpha decay, cluster radioactivity, and cold fission) have been presented in the framework of the Effective Liquid Drop Model.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nuclear Deformation on the Alpha-Decay Half-Life of Even-Even Alpha Emitters

Dimarco

Duarte

Tavares

et al. 2000

Int. J. Mod. Phys. E

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Alpha-decay half-life of even-even emitters has been calculated in terms of tunnelling through a quantum mechanical potential barrier. A multipolar expansion of Coulomb potential has been developed taking into account the nuclear quadrupole, hexadecapole, and hexacontatetrapole deformations. We show that using a free-parameter model the calculated half-lives do not vary significantly with higher order multipolarities of the daughter nucleus deformation.

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“…Since new α decays have been observed and their partial α decay half-lives T expt 1/2,α have been measured [16,17,18,19,20,26,28,29,30,31,32,33]. They are compared in the Tables 1 and 2 with the calculated values from the above-mentioned formulae using the measured Q α values.…”

mentioning

confidence: 99%

Recent α decay half-lives and analytic expression predictions including superheavy nuclei

2008

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New recent experimental α-decay half-lives have been compared with the results obtained from previously proposed formulae depending only on the mass and charge numbers of the α emitter and the Qα value. For the heaviest nuclei they are also compared with calculations using the DensityDependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulae. The correct agreement allows to provide predictions for the α decay half-lives of other still unknown superheavy nuclei from these analytic formulae using the extrapolated Qα of Audi, Wapstra The α decay process was described in 1928 [2,3] in terms of a quantum tunnelling through the potential barrier separating the mother nucleus energy and the total energy of the separated α particle and daughter nucleus. To describe the α emission two different approaches have been developed. The cluster-like theories suppose that the α particle is preformed in the nucleus with a certain preformation factor while the fission-like approaches consider that the α particle is formed progressively during the very asymmetric fission of the parent nucleus. The experimental investigation cannot unambiguously distinguish these two formation modes. However the possible one-body configurations play a minor role since in the quasi-molecular decay path investigated in the α decay process the potential barrier is governed by the balance between the repulsive Coulomb forces and the attractive proximity forces and the Q α value; consequently the barrier top is more external and lower than the pure Coulomb barrier and corresponds to two separated fragments. The difference between the two approaches appears mainly in the way the decay constant is determined. In the unified fission models [4,5] the decay constant λ is the product of the constant assault frequency ν 0 and the barrier penetrability P while in the preformed cluster models [6,7] a third factor is introduced : the cluster preformation probability P 0 .Before the theoretical explanation and description of the α decay process, Geiger and Nuttal [8] observed a dependence of the α decay partial half-life T expt 1/2,α on the mean α particle range for a fixed radioactive family and Geiger-Nuttal plots are now an expression of log 10 T α as a function of ZQ −1/2 . Since, different new relations have been proposed [5,9,10,11,12,13] to calculate log 10 T α from the measured kinetic energy of the α particle via [14,15,16,17,18,19,20]. These recent experimental results have led to new theoretical studies on the α decay; for example within the relativistic mean field theory [21], the DDM3Y interaction [22,23], the generalized liquid drop model (GLDM) [24,25] and SkyrmeHartree-Fock mean-field model [26]. The predicted halflives against α decay of these transuranium nuclei obtained with a semiempirical formula taking into account the magic numbers have also been compared with the analytical superasymmetric fission model results and the universal curves and the experimental data [13].In previous studies [5,27] both theoretic...

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Alpha decay and nuclear deformation: the case for favoured alpha transitions of even-even emitters*

Cited by 31 publications

References 38 publications

Systematic decay studies of even–even 132–138Nd, 144–158Gd, 176–196Hg and 192–198Pb isotopes

Systematic decay studies of even–even 132–138Nd, 144–158Gd, 176–196Hg and 192–198Pb isotopes

Effect of Nuclear Deformation on the Alpha-Decay Half-Life of Even-Even Alpha Emitters

Recent α decay half-lives and analytic expression predictions including superheavy nuclei

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