Properties and structure of N = Z nuclei within relativistic mean field theory

The axially deformed relativistic mean field theory with the force NLSH has been performed in the blocked BCS approximation to investigate the proper-ties 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-squaxe (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.

Theoretical study on electron impact excitation of highly charged Ne-like ions

The electron impact excitation (EIE) cross sections from the ground state to all of the 2s(2)2p(5)3l and 2s2p(6)3l(l=s, p, d) states along the Ne-like isoelectronic sequence of ions (Z = 50-57) have been calculated by using the multiconfiguration Dirac-Fock package GRASP92 and the fully relativistic distorted-wave program REIE06. In the calculations, the relativistic effects and electron correlation effects are considered systematically. Based on those calculations, the EIE cross sections along the Ne-like isoelectronic sequence of ions for different incident electron energies are discussed, and some important conclusions are drawn. We also study the influence of the correlation effects on the values of the 3C/3D line-intensity ratio [3C: (2p(1/2)3d(3/2))(1) -> 2s(2)2p(6) S-1(0), 3D: (2p(3/2)3d(5/2))(1) -> 2s(2)2p(6) S-1(0)] along the Ne-like sequence. A comparison is made between the present results and previous theoretical calculations and experimental results for the EIE cross sections in Ba-46 (+) ions, and a good agreement is obtained.

高离化态类氖离子的电子碰撞激发特性研究

利用基于多组态Dirac-Fock(MCDF)理论方法的原子结构和性质计算程序GRASP92和全相对论扭曲波电子碰撞激发计算程序REIE06,系统计算了类氖离子(Z=50—57)激发组态2s22p53l和2s2p63l(l=s,p,d)的能级结构和碰撞激发截面,总结了碰撞激发截面随入射电子能量的变化规律,讨论了实验中感兴趣的(2p1/23d3/2)1→2s22p61S0(标记为3C线)与(2p3/23d5/2)1→2s22p61S0(标记为3D线)跃迁线强度比值的沿等电子系列特性和强组态相互作用对高离化态类氖离子截面的影响.

Atomic Structures and Radiative Properties of He-like Ions in Debye Plasmas

A detailed investigation of plasma screening effects on atomic structure and transition properties are presented for He-like ions embedded in dense plasma environment. Multi-configuration Dirac-Fock calculations were carried out for these ions by considering a Debye-Huckel potential. A large-scale relativistic configuration-interaction method is adopted to calculate transition energies and transition probabilities and to allow for a systematic improvement of the calculations. Comparison of the presently calculated results with others, when available, is made.

Theoretical study of the 4d photoabsorption of the Cs+ ion

Calculations of the 4d absolute photoabsorption cross sections of the Xe-like Cs+ ion covering the energy region from 80 to 190 eV have been performed by using the multi-configuration Dirac-Fock method. The calculated cross sections are compared with the absolute experimental photoabsorption cross-section spectrum (Kjeldsen et al 2002 J. Phys. B: At. Mol. Opt. Phys. 35 2845) and other available theoretical results. In the 80-90 eV region, the discrete structure resulting from photoexcitation of a 4d electron into nf and np orbits are successfully identified. Above the 4d threshold, i.e. in the 90-190 eV energy region, a reasonable agreement between experiment and computations is found for the intense 4d -> epsilon f shape resonance.

Effects of Pairing Correlations on Formation of Proton Halo in C-9

Properties for the ground state of C-9 are studied in the relativistic continuum Hartree-Bogoliubov theory with the NLSH, NLLN and TM2 effective interactions. Pairing correlations are taken into account by a density-dependent delta-force with the pairing strength for protons determined by fitting either to the experimental binding energy or to the odd-even mass difference from the five-point formula. The effects of pairing correlations on the formation of proton halo in the ground state of C-9 are examined. The halo structure is shown to be formed by the partially occupied valence proton levels p(3/2) and p(1/2).

Relativistic Mean Field Study of the Z=117 Isotopic Chain

The properties of the Z = 117 isotopic chain are studied within the framework of the axially deformed relativistic mean field theory (RMFT) in the blocked BCS approximation. The ground-state properties, such as binging energies, deformations as well as the possible.. decay energies and lifetimes are calculated with the parameter set of NL-Z2 and compared with results from the finite range droplet model. The analysis by RMFT shows that the isotopes in the range of mass number A = 291 similar to 300 exhibit higher stability, which suggests that they may be promising nuclei to be hopefully synthesized in the lab among the nuclei Z = 117.

金属固体在重离子轰击下发射的特征X射线的能移研究

本论文的实验工作，是在兰州重离子加速器国家实验室完成的。实验中，使用ORTEC公司生产HPGe探测器测量了84MeV的12C4+重离子轰击系列金属箔生成的特征X射线。本论文研究了金属薄靶Ag、Cd、In和Sn产生的特征KX射线的能移现象。实验发现Ag、Cd、In和Sn的Kα1和Kα2X射线没有明显的能移现象，而Kβ1X、Kβ2X射线的能移却有100～200eV。对此，应用经典电磁理论详细地解释了该问题。在多组态Dirac-Fock（MCDF）程序计算的单空穴能移的基础上，分别根据实验中测量的特征KX射线的能移值和“几何”模型研究了重离子轰击下Ag、Cd、In和Sn的L、M壳层的多重电离。另外，在相同的条件下，实验测量的厚靶Au的特征LX射线能移不明显，而薄靶Au的特征LX射线却有1.5keV以上的能移。本文定性解释了该实验现象

17B的实验研究

核反应总截面是描述原子核反应基本特征的一个重要的物理量，从中可以得到有关核反应、核结构和核内核子分布的信息。利用透射法测量核的反应总截面对于模型没有依赖性，因而得到的结果更加可靠。在兰州放射性束流线（RIBLL）上利用透射法测量了17B与C、Pb靶的反应，得到了17B与C、Pb的反应总截面和去除双中子截面，同时首次尝试用CLOVER探测器测量与碎片符合的γ能谱。利用半经验的Shen公式可以很好地拟合稳定核的反应总截面的实验结果，但是并不能很好地描述17B的实验结果，说明17B具有奇异结构。采用描述不稳定核的多种密度分布形式代入零力程的Glauber模型计算17B与C的反应总截面，并与实验结果进行了比较。发现采用Skyrme－Hatree－Fock（SHF）、双Gauss、Gauss＋HO计算的密度分布形式都能够很好地拟合整个能区内的实验结果。通过各种密度分布形式提取了17B的核子密度分布，发现17B的中子密度分布有很大的弥散，并证实了17B是由核芯15B加两个价中子组成的晕结构。将Skyrme－Hatree－Fock（SHF）、双Gauss、Gauss＋HO密度分布形式，输入Glauber模型与实验结果比较，提取了17B的物质均方根半径，不同密度分布提取的均方根半径值在实验误差范围内一致，也进一步验证了17B的晕结构。采用Woods－Saxon势来描述17B核外的价中子在核芯中形成的势场，通过解薛定鄂方程来求解价中子处于特定轨道的波函数。假设17B核外的价中子处于纯的s分波和d分波都不能很好地和实验结果符合。所以认为核外的价中子应该是混合组态，通过拟合实验结果求解出s分波谱学因子的值，证明核外的价中子处在2s1/2轨道的几率更大

Synthesis, structural characterization, and ethylene polymerization behavior of the vanadium(III) complexes bearing salicylaldiminato ligands

Vanadium(III) complexes bearing salicylaldiminato ligands (2a-k) [RN=CH(Ar0)]VCl2(THF)2 (Ar C61714, R = Ph, 2a; p-CF3Ph, 2b; p-CH3Ph, 2c; 2,6-Me2Ph, 2d; 2,6-iPr2Ph, 2e; cyclohexyl, 2f; Ar = C6H3tBu(2), R = Ph, 2g; 2,6-iPr2Ph, 2h; Ar = C6H2tBU2(2,4), R = Ph, 2i; 2,6-iPr2Ph, 2j; Ar = C6H2Br2, R = Ph, 2k) were prepared from VC13(THF)3 by treating with 1.0 equiv of (RN=CH)ArOH in tetrahydrofuran (THF) in the presence of excess triethylamine (TEA).