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在相对论平均场理论的框架下,对Rn同位素链原子核的结合能、形变、同位素位移等若干基态性质进行了较详细的研究.结果表明,理论计算结果与已有的实验数据符合较好.原子核的四极形变主要出现在远离幻数的区域(N=110-124和N=129-142).而在中子数大于幻数的区域(N=127-142),十六级形变也非常明显.对电荷半径的研究显示,Rn同位素链的同位素位移曲线的斜率在中子幻数处出现明显的变化.
关键词:
相对论平均场理论
电荷半径
同位素位移
单粒子能级 相似文献
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共振是自然界普遍存在的有趣现象。在核物理领域,存在许多奇特现象,共振在其中扮演着重要角色。介绍了近期发展的RMF-CSM、RMF-CGF和RMF-CMR方法及其对原子核单粒子共振态的研究。给出了120Sn,31Ne等核的单粒子共振态的能量和宽度及其随质量数、形变的变化规律,分析了19C,31Ne和39Mg等核的晕形成的物理机制和在N=20附近能级反转的原因。特别是新发展的RMF-CMR方法,在描述稳定核和奇特核方面都取得了成功,支持Zr同位素存在巨晕的预言。Resonance is an interesting phenomenon in nature. In nuclear physics, resonance plays an important role in the formation of many exotic phenomena. This paper introduces the recently developed RMF-CSM, RMFCGF, and RMF-CMR methods and their researches on nuclear single-particle resonances. The energies and widths of the single-particle resonant states in 120Sn and 31Ne and their evolution to mass number and deformation are given. In addition, the physical mechanism of the halo formation in 19C, 31Ne and 39Mg and the cause of energy level inversion near N=20 are analyzed. In particular, the newly developed RMF-CMR approach has been successful in describing stable and exotic nuclei and supports the prediction that Zr isotopes exist in a giant halo. 相似文献
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利用形变约束的相对论平均场理论研究了Pt同位素偶-偶核的形状演化,比较了基态结合能和四极形变的理论计算值和实验值, 分析了这些核的位能曲线、单粒子能级及其随四极形变β2 的变化规律,发现从N=88到N=126, Pt同位素的基态变形从球形对称核经X(5)对称性核、演化为具有稳定形变的核,再演化为球形核的变化过程.其中, 166-172Pt是近球形核, 174Pt和192-196Pt位于球形和稳定形变之间,可能具有X(5)对称性, 176-190Pt具有稳定的变形, 198-202Pt是近球形核, 204Pt是球形核,这些结果与实验一致. 相似文献
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回顾了相对论连续谱Hartree-Bogoliubov理论对奇特核结构的描述.包括对11Li晕核的微观描述,并发现了其形成机制是由于Cooper对从1p1/2轨道被散射到2s1/2轨道;预言了滴线核的新现象——由6个中子组成的巨晕,给出了形成晕现象的条件为弱束缚与低离心位垒;解释了实际核中的赝自旋对称性;自旋轨道分裂与势能位垒弥散的关系;经典禁区内粒子对晕的影响;超重元素的结构研究等. 相似文献
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We study the reaction cross sections (σR) and root-mean-square (RMS) radii of ^8Li and ^8B, the halo-like nuclei, with stable target ^12C, ^27Al and ^9Be within the standard optical-limit Glauber model, using densities obtained from relativistic mean-field (RMF) formalisms and other types of distributions. It is found that the experimental σR can be reproduced well at high energy. The RMS radius and Ar extracted by RMF- theory and harmonic oscillator distribution are compared. larger than those of SLi. In addition, we analyze in detail the We find that the RMS radius and Ar of SB are relationship between σR and density distribution. 相似文献
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采用基于相对论平均场的耦合常数解析延拓方法研究球形核的单粒子共振态.具体计算了Zr同位素链中巨晕核的核芯核122Zr阈值附近的中子共振态的能量、宽度和波函数,其结果同相应的散射相移法的结果一致. Using analytic continuation in the coupling constant (ACCC) method within the framework of the self-consistent relativistic mean field (RMF) theory, the energies, widths and wave functions for single-particle resonant states close to the continuum threshold are evaluated. Predictions are also compared with corresponding results obtained by the scattering phase shift method. 相似文献
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Systematic trends in nuclear charge radii are of great interest due to universal shell effects and odd-even staggering (OES). The modified root mean square (rms) charge radius formula, which phenomenologically accounts for the formation of neutron-proton (np) correlations, is here applied for the first time to the study of odd-Z copper and indium isotopes. Theoretical results obtained by the relativistic mean field (RMF) model with NL3, PK1 and NL3* parameter sets are compared with experimental data. Our results show that both OES and the abrupt changes across \begin{document}$ N = 50 $\end{document} ![]()
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and 82 shell closures are clearly reproduced in nuclear charge radii. The inverted parabolic-like behaviors of rms charge radii can also be described remarkably well between two neutron magic numbers, namely \begin{document}$ N = 28 $\end{document} ![]()
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to 50 for copper isotopes and \begin{document}$ N = 50 $\end{document} ![]()
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to 82 for indium isotopes. This implies that the np-correlations play an indispensable role in quantitatively determining the fine structures of nuclear charge radii along odd-Z isotopic chains. Also, our conclusions have almost no dependence on the effective forces. 相似文献
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The axially deformed relativistic mean field theory with the force NLSH has been performed in the blocked BCS approximation to investigate the properties and structure of N=Z nuclei from Z=20 to Z=48.Some ground state quantities such as binding energies, quadrupole deformations, one/two-nucleon separation energies, root-mean-square (rms) radii of charge and neutron, and shell gaps have been calculated.The results suggest that large deformations can be found in medium-heavy nuclei with N=Z=38-42.The charge and neutron rms radii increase rapidly beyond the magic number N=Z=28 until Z=42 with increasing nucleon number, which is similar to isotope shift, yet beyond Z=42, they decrease dramatically as the structure changes greatly from Z=42 to Z=43.The evolution of shell gaps with proton number Z can be clearly observed.Besides the appearance of possible new shell closures, some conventional shell closures have been found to disappear in some region.In addition, we found that the Coulomb interaction is not strong enough to breakdown the shell structure of protons in the current region. 相似文献
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The axially deformed relativistic mean field theory with the force NLSH has been performed in the blocked BCS approximation to investigate the properties and structure of N=Z nuclei from Z=20 to Z=48. Some ground state quantities such as binding energies, quadrupole deformations, one/two-nucleon separation energies, root-mean-square (rms) radii of charge and neutron, and shell gaps have been calculated. The results suggest that large deformations can be found in medium-heavy nuclei with N=Z=38-42. The charge and neutron rms radii increase rapidly beyond the magic number N=Z=28 until Z=42 with increasing nucleon number, which is similar to isotope shift, yet beyond Z=42, they decrease dramatically as the structure changes greatly from Z=42 to Z=43. The evolution of shell gaps with proton number Z can be clearly observed. Besides the appearance of possible new shell closures, some conventional shell closures have been found to disappear in some region. In addition, we found that the Coulomb interaction is not strong enough to breakdown the shell structure of protons in the current region. 相似文献
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The influences of hyperon-hyperon interaction on the overall properties of hadronic star are investigated in the framework of relativistic mean field (RMF) theory. For certain hyperon coupling, the weaker hyperon-hyperon interaction can lead to the heavier hadronic star, which accords with the observation of heavy neutron star in X-ray binaries. We find that the threshold densities of the hyperons with larger masses are brought to a lower values with the increase of the hyperon-hyperon interaction. The possibility of the existence of hyperon star is checked with the consideration of hyperon-hyperon interaction. 相似文献
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讨论了建立在相对论平均场基态的相对论无规位相近似研究中的一致性问题. 研究表明考虑费米海和Dirac海的粒子 空穴激发对核的同位旋标量巨共振的能量有很大的影响. The fully consistent relativistic random phase approximation (RRPA) built on the relativist mean field (RMF) ground state is presented. The fully consistent RRPA requires that the nuclear RMF wave function and the RRPA renormalization are calculated in a same effective Lagrangian. A theoretically complete treatment of the RRPA at the mean field level with no sea approximation must include not only the usual particle hole states, but also the pairs formed from the occupied Fermi states and Dirac states. Effects of inclusion of Dirac sea states in various multipole excitations are investigated. Considerable effects on the isoscalar giant multipole resonances are observed. 相似文献
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In this paper,we include the density dependence behavior of the symmetry energy in the improved quark mass density dependent (IQMDD) model.Under the mean field approximation,this model is applied to investigate neutron star matter and neutron stars successfully.Effects of the density dependence of the symmetry energy on neutron stars are described. 相似文献
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We numerically explore the pasta structures and properties of low-density nuclear matter without any assumption on the geometry. We observe conventional pasta structures, while a mixture of the pasta structures appears as a metastable state at some transient densities. We also discuss the lattice structure of droplets. 相似文献
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在相对论平均场理论框架下, 研究了各种对能隙参数对O同位素偶偶核的适用性. 通过对原子核结合能和四极形变的系统计算表明, 在O同位素区域, 对能隙参数Λn和Λp均可取为0.5, 这样既简化了计算, 又可得到比较满意的结果. 相似文献