A photonuclear reaction transport model based on an isospin-dependent quantum molecular dynamics model （IQMD） is presented in the intermediate energy region, which is named as GiQMD in this study. Methodology to sim...A photonuclear reaction transport model based on an isospin-dependent quantum molecular dynamics model （IQMD） is presented in the intermediate energy region, which is named as GiQMD in this study. Methodology to simulate the course of the photonuclear reaction within the IQMD frame is described to study the photo- absorption cross section and π meson production, and the simulation results are compared with some available experimental data as well as the Giessen Boltzmann-Uehling-Uhlenbeck model.展开更多
Within the framework of the isospin-dependent quantum molecular dynamics model,the fusion cross section and fusion mechanism of neutron-deficient Pu isotopes in the reactions24,26,30Si+196Hg were investigated.We found...Within the framework of the isospin-dependent quantum molecular dynamics model,the fusion cross section and fusion mechanism of neutron-deficient Pu isotopes in the reactions24,26,30Si+196Hg were investigated.We found that the fusion cross sections are higher in the reaction with a more neutron-rich beam owing to the lower dynamical barrier.The dynamical barrier decreases with decreasing incident energy,which explains the fusion enhancement at the sub-barrier energy.The peak value of N/Z ratio in the neck region is the highest in reaction30Si+196Hg,indirectly leading to the lowest dynamical barrier.Compared with the proton density distribution,the neck region for neutrons is larger,indicating that neutrons transfer more quickly than protons,leading to a high N/Z ratio in the neck.The time distribution of the appearance of dynamical barriers is wider at lower incident energies,indicating that the fusion process took longer to exchange nucleons.The single-particle potential barrier decreases with time evolution and finally disappears at a lower impact parameter,which is favorable for fusion events.展开更多
Simulations of infinite nuclear matter at different densities,isospin asymmetries and temperatures are performed using the isospin-dependent quantum molecular dynamics(IQMD)model to study the equation of state and sym...Simulations of infinite nuclear matter at different densities,isospin asymmetries and temperatures are performed using the isospin-dependent quantum molecular dynamics(IQMD)model to study the equation of state and symmetry energy.A rigorous periodic boundary condition is used in the simulations.Symmetry energies are extracted from the binding energies under different conditions and compared to the classical molecular dynamics(CMD)model using the same method.The results show that both models can reproduce the experimental results for the symmetry energies at low densities,but IQMD is more appropriate than CMD for nuclear matter above the saturation density.This indicates that IQMD may be a reliable model for the study of the properties of infinite nuclear matter.展开更多
The deexcitation of single excited ^(112) Sn nuclei at T = 1–30 MeV is simulated using the isospin-dependent quantum molecular dynamics(IQMD) model and GEMINI model. The fragmentation mechanism, critical behavior,and...The deexcitation of single excited ^(112) Sn nuclei at T = 1–30 MeV is simulated using the isospin-dependent quantum molecular dynamics(IQMD) model and GEMINI model. The fragmentation mechanism, critical behavior,and kinematic characteristics are investigated within these two models. The results show that the IQMD model can be applied to the analysis of fragmentation processes, critical points, and slope temperature extraction. The results of IQMD are generally consistent with experimental <M_(IMF)>- Z_(bound) data. However, GEMINI can reproduce the experimental data better than IQMD for isotopic distributions.展开更多
The properties of neutrons from spectator sources produced in^(107,124)Sn+^(120)Sn collisions at 600MeV/nucleon are studied.The isospin-dependent quantum molecular dynamics(IQMD)model is used to describe the dynamical...The properties of neutrons from spectator sources produced in^(107,124)Sn+^(120)Sn collisions at 600MeV/nucleon are studied.The isospin-dependent quantum molecular dynamics(IQMD)model is used to describe the dynamical process of fragmentation,and the statistical model GEMINI is applied to simulate the secondary decay of the pre-fragments.The differential cross section and multiplicity of the neutrons emitted from the spectator source are used to prove the model's feasibility.The temperatures of the spectator source are extracted by twosource-fitting the transverse momentum distributions of the neutrons using the classical Maxwellian functions.The temperatures of the spectator sources extracted from calculations are consistent with the experimental data,those from the SMM model,and the isotopic temperature T_(HeLi).However,the participant source exhibits anomalously high temperatures.Our work suggests the possible model-errors of the IQMD+GEMINI model when describing the neutron emission from the participant source,which is reference for the further development of the model.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11421505 and 11220101005the National Basic Research Program of China under Grant No 2014CB845401the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB16
文摘A photonuclear reaction transport model based on an isospin-dependent quantum molecular dynamics model （IQMD） is presented in the intermediate energy region, which is named as GiQMD in this study. Methodology to simulate the course of the photonuclear reaction within the IQMD frame is described to study the photo- absorption cross section and π meson production, and the simulation results are compared with some available experimental data as well as the Giessen Boltzmann-Uehling-Uhlenbeck model.
基金supported by the National Natural Science Foundation of China(No.12405145)。
文摘Within the framework of the isospin-dependent quantum molecular dynamics model,the fusion cross section and fusion mechanism of neutron-deficient Pu isotopes in the reactions24,26,30Si+196Hg were investigated.We found that the fusion cross sections are higher in the reaction with a more neutron-rich beam owing to the lower dynamical barrier.The dynamical barrier decreases with decreasing incident energy,which explains the fusion enhancement at the sub-barrier energy.The peak value of N/Z ratio in the neck region is the highest in reaction30Si+196Hg,indirectly leading to the lowest dynamical barrier.Compared with the proton density distribution,the neck region for neutrons is larger,indicating that neutrons transfer more quickly than protons,leading to a high N/Z ratio in the neck.The time distribution of the appearance of dynamical barriers is wider at lower incident energies,indicating that the fusion process took longer to exchange nucleons.The single-particle potential barrier decreases with time evolution and finally disappears at a lower impact parameter,which is favorable for fusion events.
基金supported by the National Key R&D Program of China(No.2018YFA0404404)the National Natural Science Foundation of China(Nos.11925502,11935001,11961141003,11421505,11475244 and 11927901)+2 种基金Shanghai Development Foundation for Science and Technology(No.19ZR1403100)the Strategic Priority Research Program of the CAS(No.XDB34030100 and XDB34030200)the Key Research Program of Frontier Sciences of the CAS(No.QYZDJ-SSW-SLH002)。
文摘Simulations of infinite nuclear matter at different densities,isospin asymmetries and temperatures are performed using the isospin-dependent quantum molecular dynamics(IQMD)model to study the equation of state and symmetry energy.A rigorous periodic boundary condition is used in the simulations.Symmetry energies are extracted from the binding energies under different conditions and compared to the classical molecular dynamics(CMD)model using the same method.The results show that both models can reproduce the experimental results for the symmetry energies at low densities,but IQMD is more appropriate than CMD for nuclear matter above the saturation density.This indicates that IQMD may be a reliable model for the study of the properties of infinite nuclear matter.
基金supported by the National Natural Science Foundation of China(Nos.11421505,11475244,and 11175231)the National Key Research and Development Program of China(High Precision Nuclear Physics Experiments)
文摘The deexcitation of single excited ^(112) Sn nuclei at T = 1–30 MeV is simulated using the isospin-dependent quantum molecular dynamics(IQMD) model and GEMINI model. The fragmentation mechanism, critical behavior,and kinematic characteristics are investigated within these two models. The results show that the IQMD model can be applied to the analysis of fragmentation processes, critical points, and slope temperature extraction. The results of IQMD are generally consistent with experimental <M_(IMF)>- Z_(bound) data. However, GEMINI can reproduce the experimental data better than IQMD for isotopic distributions.
基金supported by the National Natural Science Foundation of China(12205026)Applied Basic Research Program of Shanxi Province(202103021223376,202203021212171)。
文摘The properties of neutrons from spectator sources produced in^(107,124)Sn+^(120)Sn collisions at 600MeV/nucleon are studied.The isospin-dependent quantum molecular dynamics(IQMD)model is used to describe the dynamical process of fragmentation,and the statistical model GEMINI is applied to simulate the secondary decay of the pre-fragments.The differential cross section and multiplicity of the neutrons emitted from the spectator source are used to prove the model's feasibility.The temperatures of the spectator source are extracted by twosource-fitting the transverse momentum distributions of the neutrons using the classical Maxwellian functions.The temperatures of the spectator sources extracted from calculations are consistent with the experimental data,those from the SMM model,and the isotopic temperature T_(HeLi).However,the participant source exhibits anomalously high temperatures.Our work suggests the possible model-errors of the IQMD+GEMINI model when describing the neutron emission from the participant source,which is reference for the further development of the model.
