Microscopic studies of production cross sections in multinucleon transfer reaction Ni58+Sn124

Abstract

Background: Multinucleon transfer reactions at low-energy collisions are considered to be promising for the production of new exotic nuclei, which are difficult to produce by other methods. Theoretical studies are required to provide reliable predictions for the experiments and to help understand the microscopic mechanism in multinucleon transfer reactions.Purpose: We provide a predictive approach for production cross sections and show how and to what extent the microscopic approach works well in multinucleon transfer reactions.Methods: We employ the $\text{TDHF}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}\text{GEMINI}$ approach, which combines the microscopic time-dependent Hartree-Fock (TDHF) model with the state-of-art statistical model $\text{GEMINI}\phantom{\rule{0.16em}{0ex}}++$, to take into account both the multinucleon transfer dynamics and the secondary de-excitation process. The properties of primary products in multinucleon transfer process, such as transfer probabilities and primary cross sections, are extracted from TDHF dynamics using the particle-number projection method. Production cross sections for secondary products are evaluated using the statistical model $\text{GEMINI}\phantom{\rule{0.16em}{0ex}}++$.Results: We investigate the influence of colliding energies and deformation orientations of target and projectile nuclei on multinucleon transfer dynamics in the reaction $^{58}\mathrm{Ni}+^{124}\mathrm{Sn}$. More nucleons are observed to transfer in the tip collision than in the side collision. The production cross sections for secondary fragments with $\text{TDHF}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}\text{GEMINI}$ calculations well reproduce the experimental measurements at energies close to the Coulomb barrier. At sub-barrier energy, the theoretical results gradually deviate from the experimental data with the increase of the number of transferred neutrons, showing the limitations of a single mean-field approximation in the TDHF approach. Possible origins for this discrepancy are discussed. The total cross sections integrated over all the neutron transfer channels are in good agreement with the experimental data for all the energies. We compare the production cross sections of $\text{TDHF}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}\text{GEMINI}$ calculations with those from GRAZING model and find that our approach gives a description as quantitatively good as the semiclassical model, although there is no adjustable parameters for the reaction dynamics in the microscopic TDHF method.Conclusions: The microscopic $\text{TDHF}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}\text{GEMINI}$ approach 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 $\text{TDHF}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}\text{GEMINI}$ method in multinucleon transfer reactions, which thus is a promising tool for predicting the properties of new reactions.