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The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus ^(52)Fe

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Science china(Physics,Mechanics & Astronomy) 2009年第10期52卷 1471-1476页

作者： LI YanSong1,2 & LONG GuiLu1,2 1 Department of Physics,Tsinghua University,Beijing 100084,china 2 center of nuclear theory,national {3. of heavy ion accelerator of Lanzhou,Lanzhou 73.000,china 1. Department of Physics Tsinghua University Beijing 100084 China 2. center of nuclear theory National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

The relativistic consistent angular-momentum projected shell model(ReCAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus *** model calculations show a reasonably good agreement with the *** backbending at 12+ is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.

关键词： ReCAPS relativistic mean field angular-momentum projection method 52Fe neutron-proton interaction

Isospin-dependent relativistic microscopic optical potential in the Dirac Brueckner-Hartree-Fock method

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Science china(Physics,Mechanics & Astronomy) 2004年第2期47卷 189-198页

作者： RONG Jian1 & MA Zhongyu1,2,3.1. china Institute of Atomic Energy, Beijing 102413. china 2. center of {3. Theoretical Physics, national laboratory of heavy ion accelerator of Lanzhou, Lan-zhou 73.000, china 3. Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100080, china Correspondence should be addressed to Rong Jian (email: jrong@***) 1. china Institute of Atomic Energy 102413 Beijing China 2. center of nuclear Theoretical Physics National Laboratory of Heavy Ion Accelerator of Lanzhou 730000 Lanzhou China 3. Institute of Theoretical Physics Chinese Academy of Sciences 100080 Beijing China

The relativistic microscopic optical potential in the asymmetric nuclear matter is studied in the framework of the Dirac Brueckner-Hartree-Fock method. A new decomposition of the Dirac structure of the nuclear self-energy in nuclear matter is adopted. The self-energy of a nucleon with E > 0 in nuclear matter is calculated with the G matrix in the Hartree-Fock approach. The optical potential of a nucleon in the nuclear medium is identified with the nucleon self-energy. The energy and asymmetric parameter dependence of the relativistic optical potentials for proton and neutron are discussed. The resulting Schroedinger equivalent potentials have reasonable behaviors of the energy dependence. The asymmetric parameter dependence of relativistic optical potentials and Schroedinger potentials are emphasized.

关键词： Dirac Brueckner Hartree-Fock, relativistic microscopic optical potential, asymmetric nuclear matter, isospin-dependence.

Critical phenomena of a nuclear system in alternative ZM models

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nuclear Science and Techniques 2000年第3期11卷 173-178页

作者： SONG Hong-Qiu (Research center of nuclear theory of {3. laboratory Of heavy ion accelerator of Lanzhou, Lanzhou 73.000 Shanghai Institute of nuclear Research, the Chinese Academy of Sciences, Shanghai 201800) 兰州原子核理论研究中心重离子加速器国家实验室甘肃兰州 730000

Alternative versions of the ZM model are extended to asymmetric nuclear matter by including p meson degree of freedom in the Lagrangian. The extended models are then used to study the thermodynamical properties of asymmetric nuclear matter at finite temperature. The critical temperature for a liquid- gas phase transition in nuclear matter and its dependence on asymmetry parameter are calculated. The limiting temperature Tlim, which reflects Coulomb instability of hot nuclei, is studied. The calculated results are compared with that given by the original ZM model.

关键词：放射性核素临界现象 ZM模型固气相变热力学稳定性核子核反应临界温度

Shape phase transitions in nuclei:Effective order parameters and trajectories

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Science china(Physics,Mechanics & Astronomy) 2011年第S1期54卷 88-97页

作者： ZHANG Yu1,2, HOU ZhanFeng2 & LIU YuXin2,3.1Department of Physics, Liaoning Normal University, Dalian 116029, china 2Department of Physics and the State Key laboratory of nuclear Physics and Technology, Peking University, Beijing 100871, china 3.4} of Theoretical nuclear Physics, national laboratory of heavy ion accelerator, Lanzhou 720000, china 1. Department of Physics Liaoning Normal University Dalian 116029 China2. Department of Physics and the State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China3. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 720000 China

We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first from the second-order phase transition in {3. above a certain boson number N (about 50), but in experiments, only those quantities, such as E(L1+)/E(02+) and B(E2; (L+2)1 → L1)/B(E2; 21 → 01), etc., of which the monotonous transitional behavior in the second-order phase transition is broken in the first order phase transition independent of N, are qualified as the effective order parameters. By implementing the originally proposed effective order parameters and the new ones, we find that the isotones with neutron number Nn = 62 are a trajectory of the second order phase transition. In addition, we predict that the transitional behavior of isomer shifts of Xe, Ba isotopes and Nn = 62 isotones is approximately monotonous due to the finiteness of nuclear system.

关键词： nuclear shape phase transition interacting boson model effective order parameter finite particle number effect transition trajectory

A phenomenological equation of state for isospin asymmetric nuclear matter

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Science china(Physics,Mechanics & Astronomy) 2009年第10期52卷 1494-1505页

作者： CHEN LieWen1,2 1 Department of Physics,Shanghai Jiao Tong University,Shanghai 200240,china 2 center of Theoretical nuclear Physics,{3. laboratory of heavy ion accelerator,Lanzhou 73.000,china Department of Physics Shanghai Jiao Tong University Shanghai 200240 China center of Theoretical nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China

A phenomenological momentum-independent(MID) model is constructed to describe the equation of state(EOS) for isospin asymmetric nuclear matter,especially the density dependence of the nuclear symmetry energy Esym(ρ).This model can reasonably describe the general properties of the EOS for symmetric nuclear matter and the symmetry energy predicted by both the sophisticated isospin and momentum dependent MDI model and the Skyrme-Hartree-Fock *** find that there exists a nicely linear correlation between Ksym and L as well as between J0/K0 and K0,where L and Ksym represent,respectively,the slope and curvature parameters of the symmetry energy at the normal nuclear density ρ0,while K0 and J0 are,respectively,the incompressibility and the third-order derivative parameter of symmetric nuclear matter at ρ*** correlations together with the empirical constraints on K0,L and Esym(ρ0) lead to an estimation of -477 MeV Ksat,2 -241 MeV for the second-order isospin asymmetry expansion coefficient for the incompressibility of asymmetric nuclear matter at the saturation point.

关键词： equation of state of nuclear matter isospin the symmetry energy

Higher order bulk characteristic parameters of asymmetric nuclear matter

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Science china(Physics,Mechanics & Astronomy) 2011年第S1期54卷 124-129页

作者： CHEN LieWen1,2 1Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, china 2center of Theoretical nuclear Physics, {3. laboratory of heavy ion accelerator, Lanzhou 73.000, china 1. Department of Physics Shanghai Jiao Tong University Shanghai 200240 China 2. center of Theoretical nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain J0 = (-3.5±95) MeV and I0 = (1473.680) MeV for the third order and fourth-order derivative parameters of symmetric nuclear matter at ρ0 and Ksym = (-100 ± 165) MeV, Jsym = (224 ± 3.5) MeV, Isym = (-13.9 ± 2025) MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at ρ0, using the empirical constraints on E0(ρ0), K0, Esym(ρ0), L, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters E0(ρ0), K0, and J0 can reasonably characterize the EOS of symmetric nuclear matter up to 2ρ0 while the symmetry energy up to 2ρ0 can be well described by Esym(ρ0), L, and Ksym.

关键词： equations of state of nuclear matter forces in hadronic systems and effective interactions symmetry energy nuclear density functional theory and extensions asymmetric matter neutron matter

How random are matrix elements of the nuclear shell model Hamiltonian?

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Science china(Physics,Mechanics & Astronomy) 2009年第10期52卷 1477-1481页

作者： SHEN JiaJie1 & ZHAO YuMing1,2,3.4 1 Department of Physics,Shanghai Jiao Tong University,Shanghai 200240,china 2 center of Theoretical nuclear Physics,{3. laboratory of heavy ion accelerator,Lanzhou 73.000,china 3.Nishina center,Institute of Physical Chemical Research(RIKEN),Hirosawa 2-1,Wako-shi,Saitama 3.1-0198,Japan 4 CCAST,World laboratory,Beijing 100080,china Department of Physics Shanghai Jiao Tong University Shanghai 200240 China center of Theoretical nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China Nishina center Institute of Physical Chemical Research (RIKEN) Hirosawa 2-1 Wako-shi Saitama 351-0198 Japan World laboratory CCAST Beijing 100080 China

In this paper we study the general behavior of matrix elements of the nuclear shell model *** find that nonzero off-diagonal elements exhibit a regular pattern,if one sorts the diagonal matrix elements from smaller to larger *** correlation between eigenvalues and diagonal matrix elements for the shell model Hamiltonian is more remarkable than that for random matrices with the same distribution unless the dimension is small.

关键词： nuclear shell model geometry property linear correlation randomize

Systematic study of survival probability of excited superheavy nuclei

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Science china(Physics,Mechanics & Astronomy) 2011年第S1期54卷 109-113页

作者： XIA ChengJun1, SUN BaoXi1, ZHAO EnGuang2,3.& ZHOU ShanGui2,3.1College of Applied Sciences, Beijing University of Technology, Beijing 100124, china 2Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, china 3.2} of Theoretical {3. Physics, national laboratory of heavy ion accelerator, Lanzhou 73.000, china Chinese Acad Sci Inst Theoret Phys Beijing 100190 Peoples R China Beijing Univ Technol Coll Appl Sci Beijing 100124 Peoples R China Ctr Theoret Nucl Phys Natl Lab Heavy Ion Accelerator Lanzhou 730000 Peoples R China

The stability of excited superheavy nuclei (SHN) with 100 Z 13. against neutron emission and fission is investigated by using a statistical model. In particular, a systematic study of the survival probability against fission in the 1n-channel of these SHN is made. The present calculations consistently take the neutron separation energies and shell correction energies from the calculated results of the finite range droplet model which predicts an island of stability of SHN around Z = 115 and N = 179. It turns out that this island of stability persists for excited SHN in the sense that the calculated survival probabilities in the 1n-channel of excited SHN at the optimal excitation energy are maximized around Z = 115 and N = 179. This indicates that the survival probability in the 1n-channel is mainly determined by the nuclear shell effects.

关键词： survival probability superheavy elements island of stability neutron emission fission

Synthesis of superheavy nuclei with ^(23.)U target

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Science china(Physics,Mechanics & Astronomy) 2009年第10期52卷 1482-1488页

作者： LIU ZuHua1,3.& BAO JingDong2,4 1 Key laboratory of Beam Technology and Material Modification of Ministry of Education,Beijing Normal University,Beijing 100875,{3. 2 Department of Physics,Beijing Normal University,Beijing 100875,{3. 3.{3. Institute of Atomic Energy,Beijing 102413.{3. 4 center of Theoretical nuclear Physics,national laboratory of heavy ion {13. of Lanzhou,Lanzhou 73.000,{3. Key laboratory of Beam Technology and Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China Department of Physics Beijing Normal University Beijing 100875 China china Institute of Atomic Energy Beijing 102413 China center of Theoretical nuclear Physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

The production of superheavy nuclei with Z=108-116 via hot fusion reactions of the neutron-rich projectiles with 23.U target is systematically *** results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z *** cross sections of the superheavy nuclei at Z = 112 and 115 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

关键词： superheavy nuclei fusion reaction cross section 23.U target