Evidence for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>α</mml:mi></mml:mrow></mml:math>clustering in heavy and superheavy nuclei

Delion, D. S.; Săndulescu, A.; Greiner, Walter

doi:10.1103/physrevc.69.044318

Cited by 88 publications

(45 citation statements)

References 52 publications

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“…For the case of higher-multipole deformations included [the (β 2i , β 3i , β 4i ) case, showing the best fit to T 1/2 data], P 0 for 14 C lies in the range of 2.21 × 10 −15 to 4.55 × 10 −19 , which is smaller, though, than the predicted values of many other models [11,16,[19][20][21], including the first estimate of Rose and Jones [5] for the calculated P 0 (α) values of, say, Refs. [34,36]. However, P 0 in the PCM of Gupta and collaborators is a relative quantity, and its value depends on the choice of Half-lives log 10 T 1/2 (s) nuclear part of the potential in the fragmentation potential V (η), just as the P value would depend on the chosen nuclear potential in the scattering potential V (R).…”

Section: Calculations and Discussionmentioning

confidence: 96%

Role of higher-multipole deformations in exoticC14cluster radioactivity

2011

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We have studied nine cases of spontaneous emission of 14 C clusters in the ground-state decays of the same number of parent nuclei from the trans-lead region, specifically from 221 Fr to 226 Th, using the preformed cluster model (PCM) of Gupta and collaborators, with choices of spherical, quadrupole deformation (β 2 ) alone, and higher-multipole deformations (β 2 , β 3 , β 4 ) with cold "compact" orientations θ c of decay products. The calculated 14 C cluster decay half-life times are found to be in nice agreement with experimental data only for the case of higher-multipole deformations (β 2 -β 4 ) and θ c orientations of cold elongated configurations. In other words, compared to our earlier study of clusters heavier than 14 C, where the inclusion of β 2 alone, with "optimum" orientations, was found to be enough to give the best comparison with data, here for 14 C cluster decay the inclusion of higher-multipole deformations (up to hexadecapole), together with θ c orientations, is found to be essential on the basis of the PCM. Interestingly, whereas both the penetration probability and assault frequency work simply as scaling factors, the preformation probability is strongly influenced by the order of multipole deformations and orientations of nuclei. The possible role of Q value and angular-momentum effects are also considered in reference to 14 C cluster radioactivity.

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Section: Calculations and Discussionmentioning

confidence: 96%

Role of higher-multipole deformations in exoticC14cluster radioactivity

2011

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“…The global calculation of α-decay half-lives presented in this article should be useful in future studies of α-decay half-lives of medium and heavy nuclei far from stability and for those of superheavy elements. Finally, we would like to mention that there are other approaches to the study of α-decay of deformed nuclei [46][47][48]. Fröman [46] investigated α decay with the deformed WKB approach, and this was further developed by Delion et al [47].…”

Section: Superheavy Nucleimentioning

confidence: 98%

“…But the penetration factor P varies significantly when the deformation effect of the daughter nucleus is taken into account. So the penetration factor is more sensitive to nuclear deformation than to other terms of the decay width [46][47][48][49]. It is thus concluded that nuclear deformation mainly affects the barrier penetration probability of the α particle.…”

Section: B Variation Of Each Term In Deformed Ddcmmentioning

confidence: 99%

Global calculation of α-decay half-lives with a deformed density-dependent cluster model

Ren

2006

Phys. Rev. C

209

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A global calculation of favored α-decay half-lives of both even-A and odd-A deformed nuclei is carried out in the framework of a deformed version of the density-dependent cluster model (DDCM). The influence of nuclear deformation on α-decay half-lives is taken into account in the deformed DDCM. The microscopic potential between the spherical α particle and the deformed daughter nucleus is evaluated numerically from the double-folding model by the multipole expansion method. The deformation and orientation dependence of the α-core potential is analyzed and discussed. The formulas of the deformed DDCM are presented in detail, and a large number of numerical calculations of medium and heavy nuclei with available data are completed. The total number of α emitters calculated in this article is 485, and this covers the nuclei with Z = 52-110. This is a complete study of α-decay half-lives on both even-A and odd-A nuclei with deformed microscopic potentials. The numerical results obtained by the deformed DDCM are in good agreement with the experimental data.

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“…(6) is obviously a quite simple approximation for the description of the complex many-body wave function of a superheavy nucleus which was analyzed e.g. in [32,33,34,35,36]. Nevertheless, the preformation factor defined as ratio P = T calc 1/2,α /T exp 1/2,α in Eq.…”

mentioning

confidence: 99%

Erratum: α-nucleus potentials, α-decay half-lives, and shell closures for superheavy nuclei [Phys. Rev. C73, 031301(R) (2006)]

Mohr¹

2006

Phys. Rev. C

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Systematic α-nucleus folding potentials are used to analyze α-decay half-lives of superheavy nuclei. Preformation factors of about several per cent are found for all nuclei under study. The systematic behavior of the preformation factors and the volume integrals of the potentials allows to predict α-decay energies and half-lives for unknown nuclei. Shell closures can be determined from measured α-decay energies using the discontinuity of the volume integral at shell closures. For the first time a double shell closure is predicted for Zmagic = 132, Nmagic = 194, and Amagic = 326 from the systematics of folding potentials. The calculated α-decay half-lives remain far below one nanosecond for superheavy nuclei with double shell closure and masses above A > 300 independent of the precise knowledge of the magic proton and neutron numbers. The α-decay of superheavy nuclei has been studied intensively in the last years [1,2,3,4,5,6,7,8,9,10]. In many papers a simple two-body model was applied [11], and in most papers a potential was derived which was able to fit the measured α-decay half-lives of the analyzed nuclei. However, most of the studies (with the exception of [2]) did not attempt to use these potentials for the description of other experimental quantities like e.g. α scattering cross sections or (n,α) or fusion reaction cross sections.Therefore, an alternative approach was followed in [12]. Now the simple two-body model has been combined with systematic α-nucleus folding potentials which are able to describe various properties, and the ratio between the calculated half-life T calc 1/2,α and the experimental half-life T exp 1/2,α has been interpreted as preformation factor P of the α particle in the decaying nucleus. Besides a systematic behavior of the volume integrals of the folding potentials, preformation factors of the order of a few per cent were found for a large number of nuclei [12,13].Only for very few light nuclei some levels have been found where a simple two-body model can exactly reproduce the experimental half-lives or widths, e.g. 12,15]. Already for 20 Ne = 16 O ⊗ α the calculated widths are somewhat larger than the experimentally observed ones [16]. Any simple two-body model with a realistic potential must provide half-lives identical or shorter than the experimental value, because the two-body model assumes a pure α cluster wave function by definition, whereas any realistic wave function is given by the sum over many different configurations. Thus, preformations of a few per cent are a quite natural finding for superheavy nuclei.The following ingredients were used in this paper. The α-nucleus potential was calculated from a double-folding procedure with an effective interaction [12,17,18]. The nuclear densities were taken from [19] T . The total potential is given by the sum of the nuclear potential V N (r) and the Coulomb potential V C (r):The Coulomb potential is taken in the usual form of a homogeneously charged sphere where the Coulomb radius R C has been chosen identically with the rms ...

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Evidence forαclustering in heavy and superheavy nuclei

Cited by 88 publications

References 52 publications

Role of higher-multipole deformations in exoticC14cluster radioactivity

Role of higher-multipole deformations in exoticC14cluster radioactivity

Global calculation of α-decay half-lives with a deformed density-dependent cluster model

Erratum: α-nucleus potentials, α-decay half-lives, and shell closures for superheavy nuclei [Phys. Rev. C73, 031301(R) (2006)]

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