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Zhenji Wu

Publications and source records attributed to Zhenji Wu.

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Impact of octupole correlation on the inverse quasifission in ${}^{160}\text{Gd}+{}^{186}\text{W}$ collisions

Multinucleon transfer (MNT) reactions offer a promising pathway to synthesize neutron-rich heavy nuclei, but the mechanism of inverse quasifission, as a key reaction channel of MNT, still remains not well understood. We employ time-dependent Hartree-Fock theory to investigate the reaction mechanism, especially the role of the octupole deformed shell in the MNT reaction of ${}^{160}\text{Gd}+{}^{186}\text{W}$. The results show that inverse quasifission occurs when the deformed projectile and target collide in near tip-tip and tip-side orientations, which favors production of neutron-rich transtarget nuclei. Interestingly, the distributions and single-particle spectra of primary products reveal that the $N=88$ octupole deformed shell in light fragments dominates inverse quasifission instead of the spherical shells of $^{208}\text{Pb}$ at a center-of-mass energy of $502.6~\text{MeV}$, thus explaining the experimental observation that the yields of the transtarget products are enhanced in the Au region. Further exploration finds that quantum shell effects in inverse quasifission exhibit energy dependence. These results demonstrate that the octupole deformed shell plays a crucial role in the inverse quasifission dynamics, significantly advancing the understanding of the MNT reaction mechanism.

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Production of proton-rich nuclei in the vicinity of 100Sn via multinucleon transfer reactions

The production of new proton-rich nuclei in the vicinity of 100Sn is investigated via multinucleon transfer reactions within the framework of microscopic time-dependent Hartree-Fock (TDHF) and statistical model GEMINI++. The TDHF+GEMINI method has demonstrated the reliable description in the multinucleon transfer dynamics and the agreement between theoretical results and experimental data is quite satisfactory in the observed transfer reactions. We reveal the production cross sections of proton-rich nuclei in 100Sn region via multinucleon transfer reactions to be several orders of magnitude higher than those measured via fusion-evaporation and projectile fragmentation experiments. About 19 new proton-rich isotopes with cross sections of larger than 1 nb are predicted to be produced in multinucleon transfer reaction of 58Ni with 112Sn. The reaction mechanisms are discussed to lead the experimental production of these previously unreported nuclei. Multinucleon transfer reactions provide a fascinating possibility to reach the proton drip-line in 100Sn region and beyond.

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Microscopic studies of production cross sections in multinucleon transfer reaction $^{58}$Ni+$^{124}$Sn

\item[Background] Multinucleon transfer reaction at low-energy collisions is considered to be a promising method for the production of new exotic nuclei, which are difficult to be produced by other methods. The theoretical studies are required to provide reliable predictions for the experiments and promote the understanding of the microscopic mechanism in multinucleon transfer reactions. \item[Purpose] We provide a predictive approach for production cross sections, and testify how and to what extent the microscopic approach works well in multinucleon transfer reaction. \item[Methods] We employ the approach TDHF+GEMINI, which combines the microscopic time-dependent Hartree-Fock (TDHF) with the state-of-art statistical model GEMINI++, to take into account both the multinucleon transfer dynamics and the secondary deexcitation process. The properties of primary products in multinucleon transfer process, such as transfer probabilities and primary cross sections, are extracted from TDHF dynamics by using the particle-number projection method. Production cross sections for secondary products are evaluated by using the statistical model GEMINI++. \item[Results] We investigate the influence of colliding energies and deformation orientations of target and projectile nuclei on multinucleon transfer dynamics in the reaction $^{58}$Ni+$^{124}$Sn...... \item[Conclusions] The microscopic approach TDHF+GEMINI reasonably reproduces the experimental data at energies close to the Coulomb barrier and well accounts for the multinucleon transfer mechanism. The present studies clearly reveal the applicability of TDHF+GEMINI method in multinucleon transfer reactions, which thus deserves as a promising tool to predict the properties of new reactions.

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Isotopic trends of quasifission and fusion-fission in the reactions $^{48}$Ca+$^{239,244}$Pu

Background: Quasifission and fusion-fission are primary mechanisms to prevent the production of superheavy elements. The recent experimental measurements reveal that the fusion-evaporation cross section in the $3n$ reaction channel of $^{48}$Ca+$^{239}$Pu is 50 times lower than using $^{244}$Pu as target nucleus. However, the precise mechanisms of this remarkable isotopic dependence are not well understood. Purpose: To understand the experimental observation of the rapid decrease of stability of superheavy nuclei as the neutron number decreases, the theoretical studies of quasifission and fusion-fission in connection with experimental production for $Z$=114 flerovium isotopes are required to investigate the possible differences in reaction mechanisms induced by these two targets. Methods: We propose an approach called TDHF+HIVAP to take into account both the evolution of dinuclear system and the deexcitation of compound nucleus, which combines the microscopic time-dependent Hartree-Fock (TDHF) method for the fusion and quasifission dynamics with the statistical evaporation model HIVAP for fusion-fission dynamics. Results: ......The quantum shell effect displays a crucial role in both the quasifission and the fusion-fission processes. The quasifission is considerably reduced and the survival probability is enhanced around one order of magnitude in the reaction using $^{244}$Pu target as compared to the $^{239}$Pu case. Conclusions: The studies by using TDHF+HIVAP method well account for the experimental observations and the present method clearly shows its applicability in the reaction mechanisms of quasifission and fusion-fission dynamics. The experimental and theoretical results encourage the use of neutron-rich targets for the production of new superheavy elements.

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