Decay and related stability aspects of the ${}_{104}{}^{266}\mathrm{Rf}*$ nucleus formed in the ${}^{18}\mathrm{O}+{}^{248}\mathrm{Cm}$ reaction

The excitation functions for the production of ${}^{262}\mathrm{Rf},{}^{261}\mathrm{Rf}$, and ${}^{260}\mathrm{Rf}$ isotopes via $4n$-, $5n$-, and $6n$-decay channels from the ${}^{266}{\mathrm{Rf}}^{*}$ compound nucleus are studied within the dynamical cluster-decay model by including ${\beta }_{2i}$ deformations and “hot-optimum” ${\theta }_i$ orientations. For angular momentum effects, both the sticking and nonsticking moments of inertia are considered. For the sticking moment of inertia $I_S$, the $4n$ and $5n$ emission data are addressed nicely by using the nuclear proximity potential Prox-00, whereas the commonly used Prox-77 is found suitable only for the $4n$-decay channel. On the other hand, in the limit of nonsticking moment of inertia $I_{NS}$, both Prox-00 and Prox-77 seem equally suitable to address all the observed neutron-decay channels in the beam energy range $E_{\mathrm{lab}}=88.2$ to 101.3 MeV. In addition to this, the role of proposed superheavy magic shells with proton magic $Z=114$, 120, 126 and neutron magic $N=184$ is also investigated, by using the $I_{NS}$ approach. The relative depth of the minimum in the fragmentation potential, or maximum peaking of the preformation factor, suggests that, among all the three magic $\left(Z,N\right)$ pairs, $Z=126$ and $N=184$ is the strongest superheavy magic shell closure required for analyzing the neutron-decay channels of the ${}^{266}{\mathrm{Rf}}^{*}$ compound nucleus.

Figure 1

Variation of the liquid drop part $V_{\mathrm{LDM}}\left(\mathrm{T}\right)$ of the total temperature-dependent binding energy as a function of light mass fragment $A_2$ (=1–4) for the decay of the ${}^{266}{\mathrm{Rf}}^{*}$ nucleus, using different magic shells for the superheavy mass region.

Figure 2

(a) Scattering potentials for the $4n$ decay of the ${}^{266}{\mathrm{Rf}}^{*}$ compound nucleus at maximum angular momentum ${\ell }_{\max }$, with use of Prox-77 and Prox-00. (b) Comparison of the barrier heights as a function of angular momentum $\ell$ for $4n$ decay of ${}^{266}{\mathrm{Rf}}^{*}$ using Prox-77 and Prox-00 within the limit of the sticking moment of inertia.

Figure 3

Comparison of the fragmentation potentials for use of sticking and nonsticking moments of inertia ($I_S$ and $I_{NS}$, respectively) of the decay fragments at (a) $\ell =0\hslash ,$ (b) ${\ell }_{\max }=23\hslash$ (maximum angular momentum for the nonsticking case), and (c) ${\ell }_{\max }$ of, respective, sticking and non-sticking moment-of-inertia.

Figure 4

Variation of (a) preformation probability $P_0$ and (b) penetration probability $P$, as a function of angular momentum for sticking and nonsticking moments of inertia at their respective neck-length parameters, for the $4n$-decay channel of ${}^{266}{\mathrm{Rf}}^{*}$ at $E_{\mathrm{lab}}=88.2$ MeV.

Figure 5

Variation of fragmentation potential as a function of light fragment mass $A_2=2$–4, 5, or 6, for nonsticking moment of inertia $I_{NS}$ at $\ell =0\hslash$ and $\ell ={\ell }_{\max }$, including ${\beta }_{2i}$ deformations, taking the magic numbers for the superheavy mass region as $Z=126$, 120, and 114 with $N=184$. The results are shown for three $E_{\mathrm{lab}}$ values, and $\Delta R$ is kept the same for each magic pair.

Figure 6

Variation of fragmentation potential as a function of angular momentum, using the nonsticking moment of inertia $I_{NS}$ for (a) $4n$-, (b) $5n$-, and (c) $6n$-decay channels, at different $E_{\mathrm{lab}}$ energies.

Figure 7

Same as for Figs. 5 and 5, respectively, but plotted to see the effect of different superheavy magic pairs $Z=126$, 120, and 114 with $N=184$ on the whole mass range of $A_2$ up to $A/2$.

Figure 8

Variation of preformation probability $P_0$ as a function of light fragment mass at $\ell ={\ell }_{\min }$ for $Z=126$, 120, 114 and $N=184$ magic pairs at (a) 88.2 MeV, (b) 94.8 MeV, and (c) 101.3 MeV beam energies for the decay of the ${}^{266}{\mathrm{Rf}}^{*}$ nucleus. $\Delta R$ is kept the same for all three cases of magic pairs.

Figure 9

Variation of channel cross sections as a function of angular momentum using three magic pairs $Z=126$, 120, and 114 with $N=184$ for (a) $4n$-, (b) $5n$-, and (c) $6n$-decay channels of the ${}^{266}{\mathrm{Rf}}^{*}$ nucleus at three $E_{\mathrm{lab}}$ energies.

Figure 10

Calculated channel cross sections for $4n,5n$, and $6n$ evaporation channels plotted as a function of $E_{\mathrm{lab}}$ for three magic pairs $Z=126$, 120, and 114 with $N=184$, fitting $\Delta R$ for one magic pair and keeping it the same for the other two cases, compared with the experimental data [5].