Am原子及其离子Am~(q+)(q=1～6)的K,L,M-X射线跃迁能和跃迁几率的理论研究（英文）

使用基于Dirac-Hartree-Fock方法的Grasp2K程序包,计算了Am原子及离子的K,L,M-X射线的跃迁能和跃迁速率。在计算中,包括了Breit相互作用、真空极化和自能等重要效应。目前研究结果与已有的其他实验和理论结果相对误差约为0.04%。此外,我们还首次计算了从Am~(1+)到Am~(6+)离子的K, L, M-X射线的跃迁能和跃迁速率。相对于中性原子,来自低离化态的跃迁能相对于中性的相应跃迁线的能量仅有轻微的偏移,这反映出外层电子几乎不影响内壳层的跃迁性质。     

高离化态氩离子产生的Kα和Kβ谱线的相对论理论研究

利用多组态Dirac-Fock方法,系统研究了不同离化度氩离子的Kα和Kβ线的结构以及内壳层旁观洞态和高n旁观电子对其结构的影响.结果表明:剥离1s、2l壳层电子而引起的Kα和Kβ线的“紫移”要强于剥离3l壳层电子的;最内层的1s旁观洞态产生的伴线与Kα和Kβ线离得较远,而较外层的2l、3l伴线与Kα和Kβ线基本重合在一起;3pnl-1snl和2pnl-1snl(n=3…6;l=0…5)类型跃迁产生的伴线的形状和位置随nl的增加逐渐接近Kα和Kβ线.     

锂等电子序列(Z=11~20) 1s23p-1s2nd(4≤n≤9)跃迁能的理论计算

利用全实加关联的方法计算类锂体系(Z=11~20) 1s23p-1s2nd(4≤n≤9)的跃迁能, 将相对论效应(电子动能的相对论修正，Darwin项，电子电子接触项以及轨道轨道相互作用)和质量极化效应作为微扰，计算了它们对体系能量的修正．计算得到的结果，与现有的实验数据比较，结果符合得很好.依据量子亏损理论，确定Rydberg系列1s2nd的量子数亏损，由此实现对任意激发态(n≥10)能量的理论预言.     

Cr~(21+)离子1s~23d-1s~2nf的跃迁能和偶极振子强度(英文)

用全实加关联方法计算了类锂Cr21+离子1s23d-1s2nf(4≤n≤9)的跃迁能和1s2nf(n≤9)态的精细结构.在类氢近似下估算了对能量的高阶相对论修正.依据量子亏损理论,确定了Rydberg系列1s2nf的量子数亏损.据此可以实现对任意高激发态(n≥10)的能量的可靠预言.计算了Cr21+离子1s23d-1s2nf(4≤n≤9)跃迁的振子强度.与量子亏损理论相结合,得到该离子从1s23d态到电离阈附近高激发束缚态间的偶极跃迁振子强度以及到相应连续态跃迁的振子强度密度,从而将Cr21+离子的这一重     

类锂离子(Z=11～20)1s~22s-1s~23p的跃迁能和振子强度

用全实加关联方法计算类锂离子 (Z =11～ 2 0 )偶极跃迁 1s2 2s 2 S - 1s2 3p 2 P , 的跃迁能。非相对论能量用Rayleigh -Ritz变分法确定 ,相对论修正和质量极化效应用微扰论计算 ,还估算了来自量子电动力学效应的修正。得到的计算结果与现有的实验数据符合得很好 ,我们关于氯的类锂离子 (Z =17) 1s2 3p态的精细结构劈裂的计算结果揭示 ,相应的实验数据明显偏离等电子序列的物理规律。还算了 1s2 2s -1s2 3p偶极跃迁的振子强度     

类锂离子(Z=11～20)1s22s-1s24p的跃迁能和振子强度

利用全实加关联方法计算了类锂离子(Z=11～20)激发态1s^24p的能量及精细结构,同时计算了1s^22s-1s^24p的跃迁能和振子强度．非相对论能量用Rayleigh-Ritz变分法确定;相对论和质量极化效应修正用微扰论计算;量子电动力学修正用有效核电荷方法计算．在能级精细结构的计算中不仅考虑了自旋-轨道相互作用还计及自旋-其他轨道相互作用．将得到的计算结果和已有实验数据及物理规律进行了比较．     

类锂体系(Z=1120) 1s24s -1s2np(5≤n≤9)跃迁能和振子强度的理论计算

利用全实加关联的方法计算类锂体系(Z=11~20) 1s24s -1s2np(5≤n≤9)的跃迁能, 将相对论效应(电子动能的相对论修正,Darwin项,电子-电子接触项以及轨道-轨道相互作用)和质量极化效应作为微扰,计算了它们对体系能量的修正．利用得到的波函数和跃迁能计算了核电荷Z=11~20的类锂离子的1s24s -1s2np(5≤n≤9)偶极跃迁的长度、速度和加速度三种规范下的振子强度,与现有的实验数据比较,结果符合得很好.     

类镁离子3s~(21)S_0-3s3p~1P_1(Z=15～103)光谱跃迁的能级和跃迁几率的相对论多组态计算

利用全相对论性多组态Dirac Fock平均能级 (MCDF AL)方法系统地计算了高离化类镁离子 3s2 1S0 - 3s3p1P1(Z =15～ 10 3)跃迁的能级间隔和跃迁几率 ,计算中考虑了重要的核有限体积效应 ,Breit修正和QED修正 ,所得结果和最近的实验数据及其它理论计算值进行了比较。     

Nb,Ag原子的K壳层和L壳层电离截面的理论计算

电子离子碰撞电离截面是模拟激光等离子体的超热电子的能谱和产额的主要过程之一.基于相对论性的电子离子碰撞的K壳层电离截面理论,计算了Nb、Ag的K壳层和L壳层电子碰撞电离截面,结果和最近的文献实验数值和其它理论数值进行了比较,计算结果比其它模型更加准确,与最近的实验结果也吻合较好,该结果可用来模拟激光等离子体的超热电子能谱和产额.     

Ti19+离子1s23d-1s2nf的跃迁能和振子强度

用全实加关联方法计算了类锂Ti19+离子1s23d～1s2nf(4≤n≤9)的跃迁能、振子强度及1s2nf(n≤9)态的精细结构劈裂.通过确定该Rydberg系列的量子数亏损,进而实现对任意高激发态(n≥10)的能量的可靠预言.将上述分立态振子强度与单通道量子亏损理论相结合,得到在电离阈附近束缚态间的跃迁振子强度与束缚态-连续态跃迁的振子强度密度,从而实现了Ti19+离子量子跃迁特性的全能域理论预言.     

X-ray photoelectron spectroscopic studies of PbO surfaces bombarded with He+, Ne+, Ar+, Xe+ and Kr+

The surface composition of PbO has been studied with X-ray photoelectron spectroscopy after bombardment with several inert gas ions of 400 eV. The results show reduction of PbO to metallic Pb with the degree of damage following the order He⁺ > Ne⁺ >Ar⁺. Both Kr⁺ and Xe⁺ did not reduce the oxide. The depth of damage varied from ≈9 Å for He⁺ to ≈1 Å for Ar⁺ bombardment. The results were compared to a collisional and a thermal model of the sputtering process.     

质谱和拉曼光谱对[M(H2O)n]+(M=Li,K)水合团簇的研究

采用质谱、拉曼光谱及理论计算对[M(H₂O)_n]+(M=Li,K)水合团簇进行了研究。质谱分析[M(H₂O)_n]+(M=Li,K)水合团簇的离子峰,推测其水溶液中最大水化数为12和13。采用拉曼光谱对浓度梯度相同的LiCl和KCl水溶液进行了讨论与比较,Li+和K+的水化作用导致~3 208 cm-1水结构拉曼峰发生了明显的变化,其中LiCl和KCl溶液的浓度分别在0~2.0和0~2.5 mol·L-1范围内,水化作用呈线性增强,浓度大于2.0和2.5 mol·L-1时,偏离线性关系,出现缔合。理论计算[M(H₂O)_n]+水合团簇结构和理论拉曼光谱表明,Li+,K+分别在n>4和n>6开始第二水化层,O-H伸缩振动频率发生了蓝移,氢键结构遭到了破坏,与实验结果一致。     

掺杂离子对白色长余辉发光材料Y2O2S:Tb3+, Eu3+,M2+ (M=Mg,Ca, Sr,Ba),Zr4+性能的影响

采用高温固相法制备了白色长余辉发光材料Y₂O₂S:Tb³⁺, Eu³⁺,M²⁺(M=Mg, Ca, Sr, Ba), Zr⁴⁺, 利用X晶体衍射、发光光谱、余辉曲线和热释光曲线等对制备的材料进行表征。结果表明:掺杂离子没有改变样品晶体结构和发射峰的位置,但对其发光强度、余辉时间及陷阱深度有较大的影响。在263 nm紫外光的激发下,469 nm和626 nm的发射分别对应于Eu³⁺的⁵D₂→⁷F₀、⁵D₀→⁷F₂跃迁,544 nm的发射对应于Tb³⁺的⁵D₄→⁷F₅跃迁,主要通过它们的混合产生白光。掺杂不同二价离子样品的余辉性能按Mg²⁺、Sr²⁺、Ca²⁺、Ba²⁺的顺序递减,其中掺杂Mg²⁺的样品,色度坐标为(0.29,0.32),陷阱深度为1.17 eV,余辉时间长达320 s(≥1 mcd/m²),表现出最佳的发光性能。     

Transition densities between the 01+, 21+, 41+, 02+, 22+, 11− and 31− states in 12C derived from the three-alpha resonating-group wave functions

All the multipole transition densities between the seven T = 0 states in ¹²C are calculated with the use of the microscopic 3α resonating-group wave functions which are obtained by dynamically solving the 3α relative motion with the total antisymmetrization taken into account exactly. The observed elastic and inelastic electron scattering form factors for the transition to the 2₁⁺, 4₁⁺, 0₂⁺, 1₁^?and 3₁^? states are well reproduced with no additional effective charge. The existence of a deformed intrinsic state for the 0₁⁺, 2₁⁺and 4₁⁺states is deduced by the analysis of the transition densities between them which are derived by the weak-coupling-type 3α wave functions; the intrinsic density distribution is illustrated. The monopole density distribution of the 0₂⁺, 2₂⁺ and 1₁^?, states is found to be much longer ranged than that of the 0₁⁺, 2₁⁺ and 4₁⁺ states; the 3₁^? state case is intermediate. On the basis of the transition densities between the 0₁⁺, 2₁⁺, 0₂⁺ and 2₂⁺ states, analysis is made of the transition between the shell-like states and the molecule-like states with a large spatial-structure change. Specific, effective nucleon-nucleon interactions are folded into the transition densities here obtained. The evident dependence of the radial shape of the folded nucleon-¹²C form factors on the choice of the interactions and the multi-step form factors for the excitation of the 0₂⁺, 1₁^? and 3₁^? states are discussed.     

Synthesis and magnetic properties of InM2+CrS4(M2+ = Mn,Fe,Co, Ni)

The crystallographic and magnetic properties of the compounds InM²⁺CrS₄(M = Mn, Fe, Co, Ni) were studied. Three of these compounds except MnInCrS₄ were antiferromagnetic. The Néel termperature and paramagnetic Curie temperature were determined to be 20 and 82K for InFeCrS₄, 36 and 115K for InCoCrS₄ and 22 and 26K for InNiCrS₄, respectively.     

Electroproduction of π0 mesons in the resonance region at q2=1.0 (GeV/c)2

Data are presented for the reaction ep → epπ⁰ at a nominal momentum transfer squared of 1.0 (GeV/c)². The data were obtained using an extracted electron beam from NINA and two magnetic spectrometers for coincidence detection of the electron and proton. Differential cross sections have been measured for isobar masses in the range 1.19–1.73 GeV/c².     

The shape of the potential energy well of impurities in KCl:Li+ and KF:M+ (M = Li, Na, K)

The shape of the potential well, which is seen by the Li⁺ impurity in KF:Li⁺ and KCl:Li⁺ is calculated, using the polarizable point ion (PPI) model and the simple shell model (SSM), in combination with a number of potentials describing the short range interaction between the ions.For both systems an off-center system is predicted. It is found that the type of short range potential affects the direction along which the absolute potential energy minimum is located. Using the PPI model or the SSM only changes the depth of the minima and their distance from the lattice site but it does not affect the symmetry of the off-center systems.A preliminary calculation of the shape of the potential well in KF:Na⁺ is presented.     

Transition moment variation in the A2Σ+ → X2Πi transition of HCl+, DCl+ and HBr+

Relative emission intensities of sixteen bands of HCl⁺ (A²Σ⁺ - X²Π_i), four bands of DCl⁺ (A²Σ⁺ - X²Π_i), and 5 bands of HBr⁺ (A²Σ - X²Π_i) have been made using both ion-beam excitation and microwave discharge sources. Intensities were determined by comparison with computer-generated spectra. Treatment of the data within the r-centroid approximation shows that in HCl⁺ the electronic transition moment decreases strongly at large $\text{r}{}_{\mathrm{v\prime v″}}$ [$\text{Re}\text{α}\text{exp}\text{(?3.6}\text{r}{}_{\mathrm{v\prime v″}}\text{)}\text{for 1.44}\text{A}\text{?}\text{< r}{}_{\mathrm{v\prime v″}}\text{< 1.82}\text{A}\text{?}$] but levels off at shorter $\text{r}{}_{\mathrm{v\prime v″}}$. DCl⁺ data agree quantitatively with HCl⁺. The variation in the HBr⁺ moment is similar, with $\text{R}\text{e}\text{α}\text{exp}\text{[?4.5}\text{r}{}_{\mathrm{v\prime v″}}\text{]}\text{for 1.58}\text{A}\text{?}\text{<}\text{r}{}_{\mathrm{v\prime v″}}\text{< 1.78}\text{A}\text{?}$.     

Coincidence electroproduction of single neutral pions in the resonance region at q2 = 0.5 (GeV/c)2

Data are presented for the reaction ep → epπ⁰ at a nominal four-momentum transfer squared of 0.5 (GeV/c)². The data were obtained using an extracted electron beam from NINA and two magnetic spectrometers for coincidence detection of the electron and proton. Details are given of the experimental method and the results are given for isobar masses in the range 1.19 – 1.73 GeV/c².     

Electron scattering from the 3.65 MeV (0+, T = 1) state in 6Li at high momentum transfer

The form factor ofthe 3.56MeV(0⁺, T = 1) state of ⁶Li has been measured for momentum transfers q = 1.0–3.0 fm^?1, and the $\text{2.18}\text{MeV}\text{(3}{}^{\mathrm{+}}\text{, T = 0)}$ and $\text{5.37}\text{MeV}\text{(2}{}^{\mathrm{+}}\text{, T = 1)}$ states have been measured up to q = 2.5 fm^?1. The 3.56 MeV form factor is analysed in terms of a phenomenological shell model with l = i valence nucleons. The radial wave functions are found to have a greater radial distribution than given by the harmonic oscillator, more closely resembling Woods-Saxon functions. The M1 form factor is found to decrease at high momentum transfer somewhat more slowly than the models predict. A technique for determining the Mλ transition current density based on the Fourier-Bessel analysis is developed and applied to the M1 transition. The M1 transition current density is obtained within a moderate error band and compared with the harmonic oscillator and Woods-Saxon densities. The M1 radiative width is 8.18 ± 0.25 eV, in agreement with previous measurements.