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

Abstract

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 ...

Complementary optical-potential analysis of -particle elastic scattering and induced reactions at low energies

“…They are also similar to those obtained by using the semi-microscopic potential III of Ref. [11] at the same energies, or derived from the analysis of α-decay [2,74].…”

“…it is used to unify the bound and scattering α-particle states [1], to analyze the superheavy nuclei α-decay halflives [2], in basic nuclear astrophysics applications [3] and for the estimation of radiation-damage effects in fusion test facilities and accelerator-driven systems. A successful global optical potential was formerly obtained by Nolte et al [4] only for α-particle energies above 80 MeV.…”

α-Cluster States in Intermediate Mass Nuclei

“…Many nuclei under study are unstable, and electron scattering data are not available in [41]. Therefore, the densities for all N = 50 nuclei in the present study were derived in the same way as in [25,36]; there it was shown that an averaged twoparameter Fermi distribution provides reasonable densities over a broad mass range by a simple scaling of the radius parameter r ∼ A 1/3 . As will be discussed later, the resuls do not show a strong dependence on the radius parameter.…”

“…Further information on the systematics of folding potentials has been obtained from the analysis of α-decay data for superheavy nuclei (e.g. [25,26,27,28,29,30,31]), for neutron-deficient p-nuclei [32,33,34], and for nuclei slightly above the doubly-magic N = Z = 50 nucleus 100 Sn [35,36]. The present work extends the study of [36] to lighter N = 50 nuclei because the double-folding potentials have proven to be reliable in such a broad range of masses.…”

Potential for α -induced nuclear scattering, reaction and decay, and a resonance-pole-decay model with exact explicit analytical solutions

“…The process of decay of alpha (α) particle from heavy and super-heavy nuclei has been studied intensively in the past few years [1][2][3][4][5][6][7][8][9][10][11][12]. In many papers a simple two-body model was applied [11][12][13] and in most papers a potential was derived that was able to fit the measured α-decay half-lives of the alpha emitters.…”