溴的类镁离子跃迁谱线和能级扩展分析

用中国原子能科学研究院HI 13串列加速器提供的 90和 130MeV的Br离子和束箔技术 ,研究了波长在 13— 2 9nm范围内Br的类Mg离子的光谱 .识别出 2 4条属于BrXXIV的“3,3”跃迁 ,即 3s2 ,3s3p ,3p2 ,3s3d和 3p3d组态之间的跃迁谱线 ,其中 19条以前未见报道 .基于实验跃迁谱线 ,19个观测能级得以确立 ,其中有 14个能级此前未见报道 .相对论Hartree Fock(HFR)方法的计算结果对所观测的能级进行了解释 .

中子物质中超流性的自能色散效应

利用扩展的 Brueckner- Hartree- Fock理论与推广的 BCS方法研究了自能的色散效应和基态关联对中子物质中超流性和能隙的影响 .研究结果表明 ,自能的色散效应使中子物质中能隙减小 ;考虑基态关联后 ,超流性将进一步减弱 .

非对称核物质的化学不稳定性与力学不稳定性

基于扩展的Skyrme有效相互作用 ,在Hartree Fock近似下对非对称核物质的化学不稳定性与力学不稳定性进行了研究 ,并与简单的三参数势 ,即所谓的软势与硬势的计算结果进行了比较 .结果发现两种模型给出的非对称核物质化学不稳定性与力学不稳定性之间的关系是完全不同的 .通过研究化学不稳定性在临界温度附近的行为发现 ,对软势与硬势 ,化学不稳定性可能出现在温度高于临界温度的气化 (全爆炸 )机制中 .而对于SKM势参数 ,化学不稳定性不会出现在温度高于临界温度的气化 (全爆炸 )机制中 .这种差别也反映在压强 密度平面上力学不稳定区与化学不稳定区的位置关系上 .进一步的计算表明 ,这种差别是由于两种模型给出的单粒子势的密度依赖形式的不同而导致的 ,这必将体现在重离子碰撞的现象中 ,从而可以作为提取核物质状态方程密度依赖形式的探针

中子星中质子比例的密度依赖

利用Hartree Fock理论 ,基于扩展的Skyrme有效相互作用 ,采用抛物线近似下对称能的密度相关形式以及 β平衡和电中性条件 ,给出了中子星中质子比例的密度依赖关系 .通过比较不同的势参数SII,SIII,SKM和SKI5下对称能强度系数的密度依赖关系研究了中子星中的质子比例 ,发现在高密时势参数SII,SIII和SKM能够给出中子星中质子消失的结果 ,这预示着致密核物质可能存在纯中子物质的基态 .同时计算表明 ,考虑中子星中 μ- 子的贡献后使质子比例增加 .

同位旋激发能研究

在扩展的Skyrme有效相互作用下 ,利用Hartree Fock理论研究了同位旋激发能与温度、密度的关系 .结果表明同位旋激发能随密度的降低以及温度的增加而降低 .同时研究了对称能与同位旋激发能的关系 ,指出对称能是同位旋激发能的一部分 ,且占相当大的比重 .最后研究了不同的势参数下 ,同位旋激发能随相对中子过剩的变化关系 ,发现同位旋激发能较强地依赖于对称能强度系数 ,而对不可压缩系数以及有效质量不太敏感 .从而为实验上通过研究同位旋激发能来提取核物质状态方程中的对称能部分指出了一条途径

对ALADIN量热曲线的新解释

基于扩展的Skyrme有效相互作用 ,在Hartree Fock近似下 ,研究了激发能与温度、密度的关系 .计算结果与ALADIN小组的实验结果十分符合 .并指出ALADIN量热曲线中的温度平台是由压缩激发能所致 .这说明出现液 气相变并不是ALADIN量热曲线的唯一解释 .从而对ALADIN量热曲线提出了一种新解释 .

Shell-model Hamiltonian from self-consistent mean-field model: N = Z nuclei

We propose a procedure to determine the effective nuclear shell-model Hamiltonian in a truncated space from a self-consistent mean-field model, e.g., the Skyrme model. The parameters of pairing plus quadrupole-quadrupole interaction with monopole force are obtained so that the potential energy surface of the Skyrme Hartree-Fock + BCS calculation is reproduced. We test our method for N = Z nuclei in the fpg- and sd-shell regions. It is shown that the calculated energy spectra with these parameters are in a good agreement with experimental data, in which the importance of the monopole interaction is discussed. This method may represent a practical way of defining the Hamiltonian for general shell-model calculations. (C) 2009 Elsevier B.V. All rights reserved.

Theoretical study of p-d hybridization in Co perovskite

The real-space recursion method and unrestricted Hartree-Fock approximation have been applied to calculate the density of states of various Co perovskite, CeCoO3, SrCoO3 and Sr1-xCexCoO3. We have studied the magnetically ordered states of these Co perovskites in an enlarged double cell, and find its various magnetic structures due to the occupancy of 3d band and its interaction with neighboring Co ions. In this study, we have studied the p-d hybridization of the three Co perovskites, we find t(2g) electrons are localized and the flat e(g) band is responsible for the itinerant behavior, and although the rare earth elements itself contribute little to the DOS at the Fermi energy, the DOS at Fermi energy and the magnetic moment changed consequently because of different valence of Co ions in these compounds and p-d hybridization effect is very important. (C) 2009 Elsevier B.V. All rights reserved.

Hyperfine quenching of the 3s3p P-3(0) level in Mg-like ions

Hyperfine quenching rates of the 3s3p P-3(0) level in Mg-like ions were calculated using the GRASP2K package based on the multi-configuration Dirac-Hartree-Fock method. Valence and core-valence correlation effects were accounted for in a systematic way. Breit interactions and QED effects were included in the subsequent relativistic CI calculations. Calculated rates were compared with other theoretical values and with experiment, and a good agreement with the latest experimental value for the Al-27(+) ion (Rosenband et al 2007 Phys. Rev. Lett. 98 220801) was found. Furthermore, we showed in detail the contributions from Breit interaction and QED effects to concerned physical properties. Finally, electronic data were presented in terms of a general scaling law in Z that, given isotopic nuclear spin and magnetic moment, allows hyperfine-induced decay rates to be estimated for any isotope along the isoelectronic sequence.

Analysis of the xuv photoabsorption spectrum of Au2+, Au3+, and Au4+

The photoabsorption processes of Au2+, Au3+, and Au4+ have been investigated experimentally and theoretically in the 70-127 eV region. Using the dual laser-produced plasma technique, the 4f and 5p photoabsorption spectrum has been recorded at 50 ns time delay and was found to be dominated by a great number of lines from 4f-5d, 6d and 5p-5d, 6s transitions, which have been identified by comparison with the aid of Hartree-Fock with configuration interaction calculations. The characteristic feature of the spectrum is that satellite lines from excited configurations containing one or two 6s electrons are more important than resonance lines, and with increasing ionization, satellite contributions from states with one 6s spectator electron gradually become more important than those with two 6s spectator electrons. Based on the assumption of a normalized Boltzmann distribution among the excited states and a steady-state collisional-radiative model, we succeeded in reproducing a spectrum which is in good agreement with experiment.

Isospin dependence of nucleon (PF2)-P-3 superfluidity in asymmetric nuclear matter

We have investigated the isospin dependence of the neutron and proton (PF2)-P-3 superfluidity in isospin-asymmetric nuclear matter within the framework of the Brueckner-Hartree-Fock approach and the BCS theory. We show that the (PF2)-P-3 neutron and proton pairing gaps depend sensitively on isospin asymmetry of asymmetric nuclear matter. As the isospin asymmetry increases, the neutron (PF2)-P-3 superfluidity becomes stronger and the peak value of the neutron (PF2)-P-3 pairing gap increases rapidly. The isospin dependence of the proton (PF2)-P-3 superfluidity is shown to be opposite to the neutron one. The proton (PF2)-P-3 superfluidity becomes weaker at a higher asymmetry and it even vanishes at high enough asymmetries. At high asymmetries, the neutron (PF2)-P-3 superfluidity turns out to be much stronger than the proton one, implying that the neutron (PF2)-P-3 superfluidity is dominated in the highly asymmetric dense interior of neutron stars.

Hot Nuclear Matter Equation of State and Finite Temperature Kaon Condensation

We perform a systematic calculation of the equation of state of asymmetric nuclear matter at finite temperature within the framework of the Brueckner-Hartree-Fock approach with a microscopic three-body force. When applying it to the study of hotka on condensed matter, we find that the thermal effect is more profound in comparison with normal matter, in particular around the threshold density. Also, the increase of temperature makes the equation of state slightly stiffer through suppression of kaon condensation.

Three-body force effect on P-3 F-2 neutron superfluidity in neutron matter, neutron star matter, and neutron stars

We investigate the effect of microscopic three-body forces on the P-3 F-2 neutron superfluidity in neutron matter, beta-stable neutron star matter, and neutron stars by using the BCS theory and the Brueckner-Hartree-Fock approach. We adopt the Argonne V18 potential supplemented with a microscopic three-body force as the realistic nucleon-nucleon interaction. We have concentrated on studying the three-body force effect on the P-3 F-2 neutron pairing gap. It is found that the three-body force effect considerably enhances the P-3 F-2 neutron superfluidity in neutron star matter and neutron stars.

Theoretical analysis of xuv photoabsorption spectra of laser-produced iodine plasmas

The 4d photoabsorption spectra of I2+, I3+, and I4+ have been obtained in the 70-127 eV region with the dual laser-produced plasma technique at time delays ranging from 400 to 520 ns. With decreasing time delay, the dominant contribution to the spectra evolves from the I2+ to the I4+ ions, and each spectrum contains discrete 4d-nf transitions and a broad 4d-epsilon f shape resonance, which are identified with the aid of multiconfiguration Hartree-Fock calculations. The excited states decay by direct autoionization involving 5s or 5p electrons, and rates for the different processes and resulting linewidths were calculated. With increasing ionization, the 4d-epsilon f shape resonance become intense and broader in going from I2+ to I3+, and then vanishes at I5+. In addition, the discrete structure of the calculated spectrum of each ion gradually approaches the corresponding shape resonance position. Based on the assumption of a normalized Boltzmann distribution among the excited states and a steady-state collisional-radiative model, we reproduced spectra which are in good agreement with experiment.

(PF2)-P-3 neutron superfluidity in neutron stars and three-body force effect

We investigate the (PF2)-P-3 neutron superfluidity in beta-stable neutron star matter and neutron stars by using the BCS theory and the Brueckner-Hartree-Fock approach. We adopt the Argonne V-18 potential supplemented with a microscopic three-body force as the realistic nucleon-nucleon interaction. We have concentrated on studying the three-body force effect on the (PF2)-P-3 neutron pairing gap. It is found that the three-body force effect is to enhance remarkably the (PF2)-P-3 neutron superfluidity in neutron star matter and neutron stars.