Global properties of even-even superheavy nuclei in macroscopic-microscopic models

Abstract

A systematic study of global properties of superheavy nuclei in the framework of macroscopic-microscopic method is performed. Equilibrium deformations, masses, quadrupole moments, radii, shell energies, fission barriers and half-lives are calculated using the following macroscopic models: Myers-Swiatecki liquid drop, droplet, Yukawa-plus-exponential, and Lublin-Strasbourg drop. Shell and pairing energies are calculated in Woods-Saxon potential with a universal set of parameters. The analysis covers a wide range of even-even superheavy nuclei from Z=100 to 122. Magic and semimagic numbers occurring in this region are indicated and their influence on the observables is discussed. The strongest shell effects appear at proton number Z=114 and at neutron number N=184. Deformed shell closures are found at N=152 and 162. Spontaneous fission half-lives are calculated in a dynamical approach where the full minimization of the action integral in a three-dimensional deformation space of $\beta$ deformations is performed. The fission half-lives obtained this way are two orders of magnitude smaller than the ones resulting from static calculations. The agreement of theoretical results and experimental data is satisfying

Synthesis of the isotopes of elements 118 and 116 in theCf249andCm245Oganessian1, Utyonkov2, Lobanov3 et al. 2006Phys. Rev. C71791751View full textAdd to dashboardCite

“…5). The best agreement is observed with the MM calculations, especially with the version of [5] ( Q α 0.2 MeV).…”

“…In comparing experiment with theory, we limit ourselves to two recent calculations with the MM model [4,5], five calculations with the HFB model (with different Skyrme or Gogny forces) [6][7][8][9][10] and two RMF calculations [11,12]. On average, the Q α = Q α (exp)-Q α (th) difference varies within 1 MeV (see Fig.…”

“…For instance, according to the macroscopic-microscopic model (MM) with Z shell = 114 [4,5], the even-even nucleus with Z = 118 and A = 294 would undergo α decay with an energy Q α = 11.9-12.1 MeV and a half-life T α ≈ 0.1 ms. In the purely microscopic Hartree-Fock-Bogoliubov (HFB) model, with Z shell = 124, 126 [6][7][8][9][10], the values Q α = 11.2-11.6 MeV and T α ≈ 1-10 ms are predicted.…”

Experimental studies of the249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotopeOganessian1, Abdullin2, Alexander3 et al. 2013Phys. Rev. C1377480View full textAdd to dashboardCite

“…Bearing in mind that SF half-lives of odd-Z nuclei could be hindered by several orders of magnitude, one can expect consid-erable weakening of the shell stabilization effect and, respectively, a decrease of T SF values for N =168 nuclei over those predicted in [24]. In accordance with this, the SF half-life for 276 Hs is calculated to be about 10 −5 s within another macroscopic-microscopic model [34]. However, in this approach T SF values for 282,284 Cn and 286 Fl are underestimated by about one order of magnitude and those for the known SF decaying even-even Rf and Hs isotopes by about three orders.…”

Fission barriers and probabilities of spontaneous fission for elements with Z≥ 100

“…While the fission probability P strongly depends on E 0 the results of calculation will be different from those where one assumes a constant E 0 = 0.5 MeV for all nuclei (see 6 e.g. [56,51]) or quantum mechanically exact values [31]. The values of the ground state energies E 0 calculated from the Eq.…”