Structure Of Superheavy Nuclei Research Articles

Manifestation of Reflection-Asymmetric Deformation in the Structure of Superheavy Nuclei

Manifestation of Reflection-Asymmetric Deformation in the Structure of Superheavy Nuclei

Structure of superheavy nuclei

Structure of superheavy nuclei

Systematic study ofα-decay properties of superheavy nuclei

The $\ensuremath{\alpha}$ decay of superheavy nuclei (SHN) is studied within the framework of the shell-model rate theory. The $\ensuremath{\alpha}$ half-lives are calculated in terms of the $\ensuremath{\alpha}$ clustering and resonance scattering amplitudes given by self-consistent models for the nuclear structure and reaction dynamics. The results and their systematics are compared with the available experimental data and with those data obtained from empirical models. The Brown relationship [B. A. Brown, Phys. Rev. C 46, 811 (1992)], which predicts a linear dependence of the $\mathrm{log}{T}_{\ensuremath{\alpha}}$ on ${Z}_{d}^{0.6}{Q}_{\ensuremath{\alpha}}^{\ensuremath{-}1/2}$, is used to obtain a relevant systematics for $\ensuremath{\alpha}$ half-lives of the observed SHN. Also, simple fit formulas are proposed for $\ensuremath{\alpha}$-half-time estimations with reduced standard errors. Comparison of experimental and calculated results provides insight into the accuracy of modern approaches for the structure of SHN with valence nucleons outside the doubly magic core.

Structure of superheavy nuclei

Properties of transactinide nuclei needed for the interpretation of spectroscopic data and for the extrapolation to the expected "island of stability" of superheavy nuclei are reviewed from a theorist's point of view in the framework of self-consistent mean-field models.

SYNTHESIS OF HEAVIEST ELEMENTS (RESULTS AND PROSPECTS)

The formation and decay properties of the heaviest nuclei with Z = 112 - 116 and 118 were studied in the reactions 238 U , 242,244 Pu , 243 Am , 245,248 Cm and 249 Cf +48 Ca . The new nuclides mainly undergo sequential α-decay, which ends with spontaneous fission. The total time of decays ranges from 0.5 ms to about 1 day, depending on the proton and neutron numbers in the synthesized nuclei. The atomic number of the new elements 115 and 113 was confirmed also by an independent radiochemical experiment based on the identification of the neutron-rich isotope 268 Db (TSF ≈ 30 h ), the final product in the chain of α-decays of the odd–odd parent nucleus 288115. The comparison of the decay properties of 29 new nuclides with Z = 104 - 118 and N = 162 - 177 gives evidence for the decisive influence of the structure of superheavy nuclei on their stability with respect to different modes of radioactive decay. The investigations connected with the search for superheavy elements in Nature (cosmic rays) and prospects of superheavy element research are also presented.

TOROIDAL STRUCTURE OF SUPER-HEAVY NUCLEI IN THE HFB THEORY

Toroidal structure of super-heavy nuclei has been analyzed within the Hartree-Fock-Bogoliubov theory with the Gogny D1S force. The global minimum of the potential energy of systems with Z > 130 has been found for nuclei in the shape of a torus. The binding energy of toroidal super-heavy nuclei is lower than the energy of the spherical nuclei by 180 MeV.

Spherical and Deformed Shell Closures in Superheavy nuclei

The structure of superheavy nuclei has been studied using themacroscopic-microscopic model. The macroscopic energy was calculatedwith the continuous medium model in which the energy is expressed as afunction of nucleon densities. The deformations and structures ofsuperheavy nuclei were systematically investigated. Calculationsreproduce well the available data of experimental α-decayenergies and half-lives. The investigation of single-particle levelsshows that the shell structure is deformation and isospin dependent.Potential-energy-surface calculations display that superheavy nucleihave in general harder shapes than the nuclei of other mass regions.

Superheavy nuclei in self-consistent models

The shell structure of superheavy nuclei is investigated within various parametrizations of relativistic and nonrelativistic nuclear mean-field models. The heaviest known even-even nuclei are used as a benchmark to estimate the predictive value of the models. From that starting point, spherical and deformed shell closures in the superheavy region are searched.