基于色散光学模型的40Ca核子散射数据计算

对钙同位素核数据的研究具有重要的理论价值和应用前景,其中⁴⁰Ca作为天然钙最主要的同位素,是一种重要的材料核素.本文采用色散光学模型对球形核⁴⁰Ca的核子弹性散射数据进行计算.通过考虑色散光学模型势中实部势的非定域性以及虚部势的壳间隙结构,实现了对⁴⁰Ca相关核子散射数据的良好描述,其中包括中子总截面、核子弹性散射角分布以及分析本领.此外,本文计算了色散光学模型势的实部体积分,其随能量的变化图像在费米能附近出现了明显的色散峰结构.     

核势和核子有效质量的同位旋相关性

在Dirac Brueckner Hartree-Fock (DBHF)理论框架下研究了核子光学势和核子有效质量的同位旋相关性. 非对称核物质的计算采用了DBHF的核子自能的Dirac结构的新的分解方法, 核子自能的实部是用G矩阵在Hartree-Fock近似下计算得到, 而虚部从极化图得到. 用核子的薛定谔等价势可以得到核子矢量有效质量. 研究表明考虑了核势的能量相关性在丰中子核物质情况下核子矢量有效质量比质子的大.     

核介质中核子–核子散射截面的BHF微观计算

在Brueckner-Hartree-Fock(BHF)框架下,计算了核介质中核子-核子(N-N)散射总截面.计算中,N-N相互作用势采用Paris势的可分离表示,单粒子谱采用连续选择.计算结果表明,质子-质子散射及质子-中子散射的总截面随核密度的增加而强烈地减小,特别是对低能散射.对结果作了简单的讨论,并与已有的一些计算结果进行了比较.     

温度相关的核子相对论微观光学势

本文将Walecka模型和热场动力学理论应用在核物质和有限核中,研究了核子在各种温度下的相对论微观光学势以及相应的薛定谔等效势和平均自由程.对于核物质,取核子的Hartree-Fock自能为光学势的实部,交换σ和ω介子的极化图为光学势的虚部.对于有限核的微观光学势通过定域密度近似获得.     

6Li与核弹性散射的微观光学势

从基本的Dirac-Brueckner-Hartree-Fock微观理论出发,得到同时包含实部和虚部的核子-核散射的微观光学势,并利用折叠模型直接获得了核-核散射参数无关的整体微观光学势.考虑到核-核散射去弹过程高级项的贡献和⁶Li的碎裂效应,在微观光学势的实部和虚部中引入了修正因子N_R,N_I.系统研究了入射粒子⁶Li与靶核¹²C,²⁸Si,关键词： 弹性散射 Dirac-Brueckner-Hartree-Fock方法 折叠模型 微观光学势     

相对论微观光学势中相互作用力程的效应

从关于相对论的核子-介子场理论的Walecka模型出发,利用由Walecka模型得到的二核子的相互作用势,对定域密度近似下的光学势进行折叠,来考虑相互作用力程在核——有限核的相对论微观光学势中的效应,并用所得到的光学势分析核子与有关核的弹性散射微分截面和有关自旋可观测量,与定域密度近似计算相比,本文的计算结果同实验值有更好的符合.     

利用双折叠模型对弹核为α的熔合垒高度和位置的系统学分析

本文系统分析了α粒子与不同的靶核熔合时, 势垒高度和位置与相互作用核的电荷数和均方根半径的关系. 通过基于密度依赖的核子-核子相互作用(CDM3Y6)的双折叠模型来计算核势. 得到了当弹核为α时垒高度和位置的参数化公式. 通过分析质量数从16到238的原子核表明, 参数化公式可以精确地再现弹核为α的熔合反应的垒高度和位置, 其精确度在±1%以内. 此外, 其结果还能很好地和实验值, 经验值, Royer, KNS, AW和亲近势的结果相符合.     

核形变随Z,N的变化与核子间相互作用的电荷无关性

用双能级模型以及与电荷无关的核子-核子相互作用研究核形变随Z,N的变化,得到了与实验大体相符的结果.     

核子相对论微观光学势、薛定谔等效势和平均自由程对核密度及温度的依赖关系

在Walecka模型的基础上,应用热动力学理论和Dirac-Bruckner-Hartree-Fock方法,研究了有限温度不同密度下核子相对论微观光学势及其相应的薛定谔等效势和平均自由程.计算结果表明,核子薛定谔等效势和平均自由程对核密度的依赖相当敏感,当核密度增大时对核密度的依赖变得更为敏感.     

基于壳模型单体密度矩阵的折叠模型质子弹性散射分析

利用折叠模型计算得到折叠势实部并结合Koning和Delaroche光学势的虚部, 计算分析了质子与^30—40S的弹性散射数据. 通过引入Woods-Saxon势下核壳模型单体密度矩阵, 消除了折叠模型计算中常用的定域近似. 分析比较了定域近似对折叠势以及弹性散射截面计算的影响. 计算结果与折叠模型以及JLM模型计算结果进行了比较.     

Nucleon--nucleon interactions in the double folding model for fusion reactions

Nucleus--nucleus potentials are determined in the framework of double folding model for M3Y--Reid and M3Y--Paris effective nucleon--nucleon (NN) interactions. Both zero-range and finite-range exchange parts of NN interactions are considered in the folding procedure. In this paper the spherical projectile--spherical target system ¹⁶O+²⁰⁸Pb is selected for calculating the barrier energies, fusion cross sections and barrier distributions with the density-independent and density-dependent NN interactions on the basis of M3Y--Reid and M3Y--Paris NN interactions. The barrier energies become lower for Paris NN interactions in comparison with Reid NN interactions, and also for finite-range exchange part in comparison with zero-range exchange part. The density-dependent NN interactions give similar fusion cross sections and barrier distributions, and the density-independent NN interaction causes the barrier distribution moving to a higher position. However, the density-independent Reid NN interaction with zero-range exchange part gives the lowest fusion cross sections. We find that the calculated fusion cross sections and the barrier distributions are in agreement with the experimental data after renormalization of the nuclear potential due to coupled-channel effect.     

Systematic studies on α-decay half-lives for super heavy nuclei

Radioactive decay of super heavy nuclei via the emission of α-particles has been studied theoretically in the preformed cluster model (PCM). The nucleus-nucleus (NN) potential is obtained by double folding the density distributions of the α-particle and the daughter nucleus with a realistic effective interaction. The M3Y effective interaction, supplemented by a zero-range pseudo-potential for exchange term, is used to calculate the NN potential. The α decay half-lives for 317 nuclei at Z=102–120 are performed in the PCM framework with the theoretical Q values extracted from the Mller-Nix-Kratz and Liran-Marinov-Zeldes mass tables and are compared with the experimental data. The calculated results are also compared with those obtained by using Q values from the Muntian-Hofmann-Patyk-Sobiczewski and Myers-Swiatecki mass estimates.     

Inferences concerning the real part of the heavy-ion optical potential through folding techniques

Analytic solutions are given for the real part of the heavy-ion optical potential through the use of single and double folding models. The effective potential between the nucleons is in the form of a sum of Yukawa terms and the distributions of the densities and the nucleon optical potential are taken to be of Woods-Saxon form. Consideration is given to the influence of the tails of the density distribution as well as that of the effective potential. Calculations suggest there is little need to delineate effective interactions with momentum components much beyond the Fermi level. This provides a rationale for realistic treatments of the effective interaction. A crucial parameter specifying the density distribution is found to be the rms radius.     

Heavy-ion optical potentials at finite temperature calculated using a complex effective interaction derived from a realistic force

Hot density distributions of heavy ions generated by a modified Thomas-Fermi calculation at finite temperature are used to calculate the optical potential using the double-folding method and a complex effective energy and density-dependent interaction deduced from a realistic NN (Reid soft-core) force in nuclear matter. The real and the imaginary part of the optical potential become more attractive when the temperature increases.     

Folding Model Analysis of Elastic Scattering of 11B from Light,Medium, and Heavy Nuclei

The elastic scattering angular distributions of ¹¹B projectile on light, medium, and heavy target nuclei including ⁷Li, ⁹Be, ¹²C, ¹⁶O, ^24,25,26Mg, ²⁷Al, ²⁸Si, ⁴⁰Ca, ⁵⁸Ni, ⁵⁹Co, ⁶⁰Ni, ¹⁹⁷Au, ²⁰⁸Pb, and ²⁰⁹Bi have been analyzed at various incident energies. The theoretical results have been obtained by using two different nuclear potentials within the framework of the optical model (OM). Firstly, the double folding potential for real part and the Wood-Saxon (WS) potential for imaginary part have been applied. Secondly, the calculations with double folding potential for both real and imaginary part have been performed and compared with the experimental data. It has been seen that the results are in very good agreement with the experimental data. Also, the volume integrals and cross-sections for each reaction have been obtained. Finally, a new and simple formula for the imaginary potential depth has been derived to clarify the nuclear interactions of ¹¹B nucleus at low energy reactions.     

Accuracy of simple folding model in the calculation of the direct part of real α−α interaction potential

The direct part of real α?α interaction potential is calculated in the simple folding model using density-dependent Brink–Boeker effective interaction. The simple folding potentials calculated from the short- and finite-range components of this effective interaction are compared with their corresponding double folding results obtained from the oscillator model wave function to establish the relative accuracy of the model. It is found that the direct part of real α?α interaction potential calculated in the simple folding model is reliable.     

A Comprehensive Theoretical Analysis of <Superscript>6,7</Superscript>Li + <Superscript>64</Superscript>Zn Elastic Scattering in a Wide Angular Range Around the Coulomb Barrier

In this paper, the elastic scattering angular distributions of ^6,7Li on ⁶⁴Zn have been investigated by using various nuclear potentials. For this, we use the phenomenological Woods-Saxon potential, the real double folding potential with the density-independent M3Y effective interaction supplemented with an imaginary part in Woods-Saxon form and the double folding potentials multiplied with a normalization factor of the real and imaginary parts via the density-independent and CDM3Y6 density-dependent versions of the M3Y effective interaction have been used. The results have been compared with each other as well as with the experimental data. It has been observed that the agreement between the theoretical results and earlier reported data is perfect. Finally, the change of the total reaction cross sections with energy has been investigated.     

On the nuclear interaction potential in the reactions with heavy ions

The interaction potential of heavy ions⁴He,⁶Li,¹²C and¹⁶O is constructed in the folding model. The density distribution of nuclear matter for these nuclei is calculated in the framework of the hyperspherical function method. For the calculation of the folding potentials we have employed the Skyrme nucleon-nucleon forces. The influence of several effects on the results of calculations is studied: the role of the three-body forces of the nucleon-nucleon interaction, dependence of the folding potential on the mass numbers of the colliding nuclei and the possibility of observing the monopole resonance in the ion inelastic scattering. Using our folding potential as a real part of the optical potential we have calculated the differential cross section of elastic scattering of⁶Li from¹²C at laboratory energy of lithium ionsT _L =90.0 MeV. Reasonable agreement with experiment is obtained.