Spontaneous-fission half-lives of deformed superheavy nuclei

Eleven new heaviest isotopes of elementsZ=105toZ=117identified among the products ofOganessian1, Abdullin2, Bailey3 et al. 2011Phys. Rev. C1255350View full textAdd to dashboardCite

“…The experimental data for the three even-even isotopes 282 Cn (N = 170) and 284 Cn/ 286 114 (N = 172) [5] confirm such behavior (log T SF (s) ≈ -3.1 and -1.0/-0.6, respectively). The SF half-lives for even-odd 279 Ds and 281 Ds are in agreement with this pattern (log T SF (s)≈ -0.7 and 1.0) and would be in quantitative agreement with predictions [47] and measured T SF values for 282 Cn, 284 Cn and 286 114, if one applied the same hindrance factor of three orders of magnitude for T SF caused by the unpaired neutron in both Ds isotopes. Thus, when going from 279 Ds (N = 169) to 282 Cn (N = 170), then to 281 Ds (N = 171), and 284 Cn/ 286 114 (N = 172) the unhindered SF half-lives would increase by about one order of magnitude for each neutron number from 0.2 ms to 1 ms and further to 10 ms and 100/260 ms, respectively.…”

“…Experimental half-lives together with predicted β + /ECdecay energies for the isotopes 266,268,270 Db are in agreement with T β vs. Q β systematics for Np-Db isotopes. This indicates that the heaviest odd-odd isotopes have significant probability of decaying by β + /EC decay, leading to the spontaneous fission of even-even Rf isotopes for which T SF =23 s, 1.4 s, and 20 ms are predicted [47]. Values of the observed half-lives leading to fission for 267 Db as well as 281 Rg are somewhat lower than the bulk of β + /EC data for lighter isotopes.…”

“…In the systematics of T SF (N ) the decrease in the halflife of the even-Z nuclei with increasing neutron number in the region of nuclei with N > 162 gives way to a strong increase in stability associated with the effect of approaching the spherical shell N = 184 [47,48]. Minimum values of T SF are characteristic of the transition region N = 168-170, where the effect of nuclear shells is at a minimum.…”

“…Predicted SF half-lives of even-even nuclei with Z = 110 -114 and N = 168 -176 [47,48] differ by less than one order of magnitude for each N ; their logarithms increase from about -1.8 to -1.5 for N =168, 170, and become increasingly larger for N = 172, 174, 176 (log T SF (s)≈ 0.4, 2.8 and 5.1, respectively). The experimental data for the three even-even isotopes 282 Cn (N = 170) and 284 Cn/ 286 114 (N = 172) [5] confirm such behavior (log T SF (s) ≈ -3.1 and -1.0/-0.6, respectively).…”

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

“…HLs: 0.8 ms in 282 Ds, 97 ms in 284 Ds and 130 ms in 286 Fl. The values predicted some time ago [81] from the sub-barrier action minimisation based on the WS model were, respectively, 71 ms, 4 s and 1.5 s (1-2 orders of magnitude overestimate; only axial deformations were included in [81], but axially symmetric shapes at the barrier in these nuclei were actually confirmed in [32]). One can observe that the FRLDM barriers for Z = 112, 114 are much higher than in the WS model and could hardly produce HLs in agreement with experiment.…”