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Dynamics of light nuclei produced in the massive transfer reactions

Zi-Han Wang, Zhao-Qing Feng

TL;DR

The study addresses how light clusters are emitted in massive transfer reactions near the Coulomb barrier. It extends the dinuclear-system (DNS) model by incorporating cluster transfer into the dissipative collision dynamics to compute capture, transfer, and preequilibrium emission processes. Key findings show neutron emission dominates while α emission is comparable to hydrogen isotopes; kinetic-energy spectra follow Boltzmann-like shapes influenced by Coulomb barriers, and angular distributions align with multinucleon transfer fragment patterns. This work advances understanding of MNT fragment formation and energy-angular momentum dissipation, with implications for guiding future experiments at facilities like HIAF.

Abstract

Within the framework of the dinuclear system (DNS) model by implementing the cluster transfer into the dissipation process, we systematically investigated the energy spectra and the angular distribution of the preequilibrium clusters (n, p, d, t, $^{3}$He, $α$, $^{6,7}$Li, $^{8,9}$Be) in the massive transfer reactions of $^{12}$C+$^{209}$Bi, $^{14}$N+$^{159}$Tb, $^{14}$N+$^{169}$Tm, $^{14}$N+$^{181}$Ta, $^{14}$N+$^{197}$Au, $^{14}$N+$^{209}$Bi, $^{58,64,72}$Ni+$^{198}$Pt near the Coulomb barrier energies. It is found that the neutron emission is the most probable in comparison with the charged particles and the $α$ yields are comparable with the hydrogen isotopes in magnitude. The preequilibrium clusters are mainly produced from the projectile-like and target-like fragments in the evolution of dinuclear system. The kinetic energy spectra manifest the Boltzmann distribution and the Coulomb potential influences the structure. The preequilibrium clusters follows the angular distribution of multinucleon transfer fragments.

Dynamics of light nuclei produced in the massive transfer reactions

TL;DR

The study addresses how light clusters are emitted in massive transfer reactions near the Coulomb barrier. It extends the dinuclear-system (DNS) model by incorporating cluster transfer into the dissipative collision dynamics to compute capture, transfer, and preequilibrium emission processes. Key findings show neutron emission dominates while α emission is comparable to hydrogen isotopes; kinetic-energy spectra follow Boltzmann-like shapes influenced by Coulomb barriers, and angular distributions align with multinucleon transfer fragment patterns. This work advances understanding of MNT fragment formation and energy-angular momentum dissipation, with implications for guiding future experiments at facilities like HIAF.

Abstract

Within the framework of the dinuclear system (DNS) model by implementing the cluster transfer into the dissipation process, we systematically investigated the energy spectra and the angular distribution of the preequilibrium clusters (n, p, d, t, He, , Li, Be) in the massive transfer reactions of C+Bi, N+Tb, N+Tm, N+Ta, N+Au, N+Bi, Ni+Pt near the Coulomb barrier energies. It is found that the neutron emission is the most probable in comparison with the charged particles and the yields are comparable with the hydrogen isotopes in magnitude. The preequilibrium clusters are mainly produced from the projectile-like and target-like fragments in the evolution of dinuclear system. The kinetic energy spectra manifest the Boltzmann distribution and the Coulomb potential influences the structure. The preequilibrium clusters follows the angular distribution of multinucleon transfer fragments.
Paper Structure (8 sections, 39 equations, 8 figures, 1 table)

This paper contains 8 sections, 39 equations, 8 figures, 1 table.

Table of Contents

  1. I. Introduction
  2. II. Brief description of the model
  3. 2.1 The capture cross section of binary system overcoming the Coulomb barrier
  4. 2.2 The nucleon and cluster transfer dynamics
  5. 2.3 The preequilibrium cluster emission
  6. III. Results and discussion
  7. IV. Conclusions
  8. Acknowledgements

Figures (8)

  • Figure 1: The potential energy surfaces in the reactions of (a) $^{14}$N+$^{209}$Bi and (b) $^{64}$Ni+$^{198}$Pt, respectively.
  • Figure 2: Temporal evolution of the preequilibrium cluster emission in the reactions of (a) $^{14}$N + $^{159}$Tb and (b) $^{14}$N + $^{169}$Tm at the beam energy of 115 MeV.
  • Figure 3: The same as in Fig. 2, but for the collisions of $^{14}$N on $^{181}$Ta and $^{197}$Au, respectively.
  • Figure 4: Kinetic energy spectra of the light nuclei produced in the reactions of (a) $^{14}$N+$^{159}$Tb, (b) $^{169}$Tm and (c) $^{181}$Ta at E$_{lab}$=115 MeV, respectively.
  • Figure 5: Kinetic energy spectra of the preequilibrium clusters produced in collisions of (a) $^{12}$C+$^{209}$Bi at E$_{lab}$=73 MeV and (b) $^{14}$N+$^{209}$Bi at E$_{lab}$=115 MeV, respectively. The available experimental data are shown for comparison from HIRFL for the reaction of $^{12}$C+$^{209}$Bi Jin1980 (left panel) and from RIKEN for $^{14}$N+$^{209}$Bi Ut1980, respectively.
  • ...and 3 more figures