Energy-Dependence of Nucleus-Nucleus Potential and Friction Parameter in Fusion Reactions

Abstract

Applying a macroscopic reduction procedure on the improved quantum molecular dynamics (ImQMD) model, the energy dependences of the nucleus-nucleus potential, the friction parameter, and the random force characterizing a one-dimensional Langevin-type description of the heavy-ion fusion process are investigated. Systematic calculations with the ImQMD model show that the fluctuation-dissipation relation found in the symmetric head-on fusion reactions at energies just above the Coulomb barrier fades out when the incident energy increases. It turns out that this dynamical change with increasing incident energy is caused by a specific behavior of the friction parameter which directly depends on the microscopic dynamical process, i.e., on how the collective energy of the relative motion is transferred into the intrinsic excitation energy. It is shown microscopically that the energy dissipation in the fusion process is governed by two mechanisms: One is caused by the nucleon exchanges between two fusing nuclei, and the other is due to a rearrangement of nucleons in the intrinsic system. The former mechanism monotonically increases the dissipative energy and shows a weak dependence on the incident energy, while the latter depends on both the relative distance between two fusing nuclei and the incident energy. It is shown that the latter mechanism is responsible for the energy dependence of the fusion potential and explains the fading out of the fluctuation-dissipation relation.

14 pages, 10 figures; Phys. Rev. C, in press

References in corpus (16)

• Energy dependence of nucleus-nucleus potential close to the Coulomb barrier
• Theoretical study of the synthesis of superheavy nuclei with Z= 119 and 120 in heavy-ion reactions with trans-uranium targets
• Heavy-ion interaction potential deduced from density-constrained TDHF calculation
• One-body energy dissipation in fusion reaction from mean-field theory
• Dynamical analysis on heavy-ion fusion reactions near Coulomb barrier
• Applications of Skyrme energy-density functional to fusion reactions for synthesis of superheavy nuclei
• Conservation Properties in the Time-Dependent Hartree Fock Theory
• Study of ${}^{64}$Ni+${}^{132}$Sn Fusion with Density Constrained TDHF Formalism
• Dissipation dynamics and spin-orbit force in time-dependent Hartree-Fock theory
• Dynamical deformation effects in subbarrier fusion of ${}^{64}$Ni+${}^{132}$Sn
• Boost-invariant mean field approximation and the nuclear Landau-Zener effect
• Dynamical nucleus-nucleus potential and incompressibility of nuclear matter
• Dynamical nucleus-nucleus potential at short distances
• Understanding the symmetry energy using data from the ALADIN-2000 Collaboration taken at the GSI Large Neutron Detector
• Non-Markovian dynamics with fermions
• Difficulties in probing density dependent symmetry potential with the HBT interferometry

Cited by in corpus (1)

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