Studies of low-lying states of even-even Xe isotopes within the nucleon pair approximation

We study the relevance of nucleon pairs with higher spins, in addition to spin-zero and spin-two pairs (i.e., S D pairs), in low-lying states of even-even Xe nuclei. By including those higher-spin pairs in our configuration, we recalculate energy level schemes, elec trical quadrupole moments, magnetic moments and electric quadrupole transition rates, for low-lying states of even-even 128-142Xe nuclei. The agreement between our calculated results and the experimental data is substantially improved in compari...     

The Gamow shell model with realistic interactions: a theoretical framework for ab initio nuclear structure at drip-lines

Ab initio approaches are among the most advanced models to solve the nuclear many-body problem. In particular, the no-core–shell model and many-body perturbation theory have been recently extended to the Gamow shell model framework, where the harmonic oscillator basis is replaced by a basis bearing bound, resonance and scattering states, i.e. the Berggren basis. As continuum coupling is included at basis level and as configuration mixing takes care of inter-nucleon correlations, halo and resonance nuclei can be properly described with the Gamow shell model. The development of the no-core Gamow shell model and the introduction of the $\hat{\bar{Q}}$-box method in the Gamow shell model, as well as their first ab initio applications, will be reviewed in this paper. Peculiarities compared to models using harmonic oscillator bases will be shortly described. The current power and limitations of ab initio Gamow shell model will also be discussed, as well as its potential for future applications.     

The nucleon pair approximation(NPA) of the shell model

In this paper we discuss the nucleon pair approximation of the shell model,based on our recent results which include a brief introduction to its framework and validity.We exemplify this model by studies of low-lying states for odd-odd nuclei in the mass number A-210 region.     

SD-pair structure in the pair approximation of the nuclear shell model

In this paper we study the structure coeficients of collective pairs with spin zero and spin two (SD) in a number of configurations by a few realistic nuclei. We investigate the robustness of these structure coeffcients with respect to different configurations and the evolution of SD-pair structure coeffcients with valence nucleon number.     

Collective bands of the positive parity states inf 7/2 shell nuclei

Collective bands of the positive parity states in odd-A f _7/2 shell nuclei are described in the framework of deformed Hartree-Fock theory by projecting states from lowest energy intrinsic states with (d ₃ ^2/−1 f ₇ ^2/n+1 ) one hole configurations. In the calculation empirical (d _3/2 −f _7/2)² effective matrix elements have been used to test the tacit assumptions of the Bansal and French model.     

Quark distributions in nuclei and nuclear effects on nucleon structure functions

Extended quark distribution functions are presented obtained by fitting a large amount of experi-mental data of the ι-A DIS process on the basis of an improved nuclear density model. The experimental data of ι-A DIS processes with A≥ 3 in the region 0.0010 ≤ x ≤ 0.9500 are quite satisfactorily described by using the extended formulae. Our knowledge of the influence of nuclear matter on the quark distributions is deepened.     

94Mo高自旋态能级纲图

通过重离子融合蒸发反应^16O(^82Se 4n)^94Mo布局了^94Mo核的高自旋态．利用多探头探测器阵列GASP进行了在束γ测量，从而重新研究了^94Mo核的高自旋态能级结构．基于新发现的一些重要的连接跃迁，对^94Mo核的高自旋态能级纲图做了重要修改．将新的能级结构与壳模型计算进行了比较和讨论．结果表明要正确的描述^94Mo核的高自旋态(自旋值大于14)能级结构，应考虑价中子在d5／2，g7／2和h11/2轨道上的激发．     

Quark distributions in nuclei and nuclear effects on nucleon structure functions

Extended quark distribution functions are presented obtained by fitting a large amount of experimental data of the l-A DIS process on the basis of an improved nuclear density model. The experimental data of l-A DIS processes with A≥3 in the region 0.0010≤x≤0.9500 are quite satisfactorily described by using the extended formulae. Our knowledge of the influence of nuclear matter on the quark distributions is deepened.     

Frontiers and challenges of the nuclear shell model

Two recent developments of the nuclear shell model are presented. One is a breakthrough in computational feasibility owing to the Monte Carlo Shell Model (MCSM). By the MCSM, the structure of low-lying states can be studied with realistic interactions for a wide, nearly unlimited basically, variety of nuclei. The magic numbers are the key concept of the shell model, and are shown to be different in exotic nuclei from those of stable nuclei. Its novel origin and robustness will be discussed. Received: 1 May 2001 / Accepted: 4 December 2001     

改进的核密度模型与强子-核Drell-Yan过程中的核效应

提出了改进的核密度模型，用唯象的方法找到了束缚核子内价夸克和海夸克的核效应的参数公式，其中利用了核密度与原子核的平均结合能之间的联系. 利用该模型所得到的束缚核子内部分子分布函数，对强子与核的Drell-Yan过程的核效应给出了满意的解释, 深化了对原子核内夸克分布受核效应影响的认识. 关键词： 核密度模型 核效应 强子-核Drell-Yan过程     

核子配对壳模型计算中的多体效应

戴断到Ｓ,Ｄ子空间的核子配对壳模型用于原子核＾１２８－１３４Ｘｅ和＾１３０－１３６Ｂａ的计算。为考虑多体效应,Ｓ,Ｄ对分别用变分法和Ｔａｍｍ－Ｄａｎｃｏｆｆ近似给定。用一个含有三个参数的哈密顿量系统地描述了Ｘｅ和Ｂａ同位素的能谱,本征态和电磁跃迁的强度。所得结果和实验结果符合得较好,并且在一定程度上改善了用表面δ相互作用决定的Ｓ,Ｄ对所得结果中的不足之处。     

Application of shell model in molecular dynamics simulation to MgO

The P－V－T equation of state of MgO has been simulated under high pressure and elevated temperature using the molecular dynamics (MD) method with the breathing shell model (BSM). It is found that the MD simulation with BSM is very successful in reproducing accurately the measured molar volumes of MgO over a wide range of temperature and pressure. In addition, the MD simulation reproduces accurately the measured volume compression data of MgO up to 100GPa at 300K. It is demonstrated that the MD simulated P－V－T equation of state of MgO could be applied as a useful internal pressure calibration standard at elevated temperatures and high pressures.     

核子配对壳模型计算中的多体效应

截断到S ,D子空间的核子配对壳模型用于原子核1 2 8- 1 34 Xe和1 30 - 1 36 Ba的计算。为考虑多体效应 ,S ,D对分别用变分法和Tamm Dancoff近似给定。用一个含有三个参数的哈密顿量系统地描述了Xe和Ba同位素的能谱 ,本征态和电磁跃迁的强度。所得结果和实验结果符合得较好 ,并且在一定程度上改善了用表面δ相互作用决定的S ,D对所得结果中的不足之处。     

Frontiers and challenges of nuclear shell model

Two recent developments of the nuclear shell model are presented. One is a breakthrough in computational feasibility owing to the Monte Carlo Shell Model (MCSM). By the MCSM, the structure of low-lying states can be studied with realistic interactions for a wide, nearly unlimited basically, variety of nuclei. The magic numbers are the key concept of the shell model, and are shown to be different in exotic nuclei from those of stable nuclei. Its novel origin and robustness will be discussed. Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002 RID="a" ID="a"e-mail: otsuka@phys.s.u-tokyo.ac.jp     

WLW 原子核质量模型在r过程研究中的应用

本工作利用最近提出的WLW宏观-微观原子核质量模型, 在经典 r过程框架下 很好地描述了太阳系r过程核素丰度分布. 与常用的FRDM质量模型相比, 新计算更好地再现了A≈ 135和A≈ 180质量区的太阳系r过程核素丰度, 尤其 避免了其他相似计算中A=135 附近出现的 与观测不符的丰度峰问题. 分析表明, 这种差异可能暗示WLW更为合理地处理了壳结构和对称能.     

Application of the three body force shell model to the lattice dynamics of calcium oxide

The lattice dynamics of GaO has been studied on the basis of the three body force shell model, which takes into account the effect of many body interactions in the lattice potential. The dispersion curves obtained by plottingω vsq agree fairly well with the experiments. It is concluded that the value of the molecular electronic polarizability of the solid must be must small than that determined experimentally which suggests that the interaction system in the solid may have a substantial covalent character.     

迈耶夫人与核壳层模型

介绍了迈耶夫人的生平和她对物理学的主要贡献,回顾了她从幻数入手,继而建立原子核壳层模型的过程,以及由此带给我们的启示.