Effect of cluster transfer on the production of neutron-rich nuclides near $N=126$ in multinucleon-transfer reactions

The cluster transfer in multinucleon-transfer reactions near Coulomb barrier energies is implemented into the master equations in the dinuclear system model, in which deuterons, tritons, ${}^3\mathrm{He}$, and $\alpha$ particles are taken into account. The effects of cluster transfer and dynamical deformation on the formation of primary and secondary fragments are systematically investigated. It is found that the inclusion of cluster transfer is favorable for fragment formation by increasing the transferring nucleons and leads to a broad mass distribution. The isotopic cross sections of wolfram, osmium, radon, and francium in ${}^{136}\mathrm{Xe}+{}^{208}\mathrm{Pb}$ reactions at an incident energy of $E_{\mathrm{c}.\mathrm{m}.}=450$ MeV are nicely consistent with the Argonne data. The new neutron-rich isotopes of wolfram and osmium are predicted with cross sections above 10 nb. The production mechanism of neutron-rich heavy nuclei near $N=126$ in ${}^{58,64,72}\mathrm{Ni}+{}^{198}\mathrm{Pt}$ reactions is investigated thoroughly. The cross sections for producing the neutron-rich isotopes of platinum, iridium, osmium, and rhenium in the multinucleon-transfer reactions ${}^{64}\mathrm{Ni}+{}^{198}\mathrm{Pt}$ and ${}^{72}\mathrm{Ni}+{}^{198}\mathrm{Pt}$ at center-of-mass energies of 220 and 230 MeV are estimated and proposed for future experiments.

Figure 1

Comparison of the MNT fragments in collisions of ${}^{48}\mathrm{Ca}+{}^{238}\mathrm{U}$ at the beam energy of 4.76 MeV/nucleon with different cases of cluster transfer (deuteron, triton, ${}^3\mathrm{He}$, and $\alpha$ particle) and dynamical evolution of quadrupole deformation of DNS fragments. The available experimental data are taken from Ref. [55].

Figure 2

Isotopic distributions of the primary and secondary fragments for (a) wolfram (W), (b) osmium (Os), (c) radon (Rn), and (d) francium (Fr) production in the MNT reactions of ${}^{136}\mathrm{Xe}+{}^{208}\mathrm{Pb}$ at ${\mathrm{E}}_{\mathrm{c}.\mathrm{m}.}=450$ MeV with the effects of cluster transfer and dynamical deformation and compared with the Argonne data [25]. The open symbols denote the new isotopes [59].

Figure 3

The secondary fragment production in the MNT reactions of ${}^{58,64,72}\mathrm{Ni}+{}^{198}\mathrm{Pt}$ near the shell closure with $N=126$ (s) and $Z=82$ (b), respectively.

Figure 4

Isotopic distributions of platinum (Pt), iridium (Ir), osmium (Os), and rhenium (Re) in the MNT reactions of ${}^{64}\mathrm{Ni}+{}^{198}\mathrm{Pt}$ and ${}^{72}\mathrm{Ni}+{}^{198}\mathrm{Pt}$ at center-of-mass energies of 210, 220, and 230 MeV, respectively.