Theoretical energy level spectra and transition data for 4p4d, 4p4d4f,and 4p4d configurations of W

The ab initio   quasirelativistic Hartree–Fock method developed specifically for the calculation of spectral parameters of heavy atoms and highly charged ions is used to derive transition data for a multicharged tungsten ion. The configuration interaction method is applied to include electron correlation effects. The relativistic effects are taken into account in the Breit–Pauli approximation for quasirelativistic Hartree–Fock radial orbitals. The energy level spectra, radiative lifetimes and Lande g$g$-factors are calculated for the 4p⁶4d², 4p⁶4d4f, and 4p⁵4d³ configurations of the ion W³⁶⁺. The transition wavelengths, spontaneous transition probabilities, oscillator strengths, and line strengths for the electric dipole, electric quadrupole, electric octupole, and magnetic dipole transitions among the levels of these configurations are tabulated.     

The energy levels and radiative transition probabilities for electric quadrupole and magnetic dipole transitions among the levels of the ground configuration, [Kr]4d4f, of W

Large-scale multiconfiguration Hartree-Fock and Dirac-Fock calculations have been performed for the ground configuration, [Kr]4d¹⁰4f⁴, energy levels of the W²⁴⁺ ion. The relativistic corrections were taken into account in the quasirelativistic Breit-Pauli and fully relativistic Breit (taking into account QED effects) approximations. The role of correlation, relativistic, and QED corrections is discussed. Line strengths, oscillator strengths, and transition probabilities in the Coulomb and Babushkin gauges are presented for the electric quadrupole (E2) transitions among these levels. The magnetic dipole transitions are also investigated. Dependence of the E2 transition probabilities on the gauge condition of the electromagnetic field potential is studied as well.     

Beam-foil study of 2p43s, 3p and 3d configurations in S VIII

The spectrum of seven times ionised sulphur, S VIII, has been observed from 450 to 1150 Å. About 30 lines have been identified as combinations between levels of the 2s²2p⁴3s, 3p and 3d configurations. The identifications are supported by isoelectronic comparisons along the FI isoelectronic sequence.     

Energies and E1, M1, E2, and M2 transition rates for states of the 2s2p, 2s2p,and 2p configurations in nitrogen-like ions between F III and Kr XXX

Based on relativistic wavefunctions from multiconfiguration Dirac–Hartree–Fock and configuration interaction calculations, E1, M1, E2, and M2 transition rates, weighted oscillator strengths, and lifetimes are evaluated for the states of the (1s²)2s²2p³,2s2p⁴, and 2p⁵ configurations in all nitrogen-like ions between F  III and Kr  XXX. The wavefunction expansions include valence, core–valence, and core–core correlation effects through single–double multireference expansions to increasing sets of active orbitals. The computed energies agree very well with experimental values, with differences of only 300–600 cm⁻¹ for the majority of the levels and ions in the sequence. Computed transitions rates are in close agreement with available data from MCHF-BP calculations by Tachiev and Froese Fischer [G.I. Tachiev, C. Froese Fischer, A&A 385 (2002) 716].     

Electric-dipole allowed and intercombination transitions among the 3d, 3d4s and 3d4p levels of Fe IV

Oscillator strengths and transition rates for the electric-dipole (E1) allowed and intercombination transitions among 3d⁵, 3d⁴4s and 3d⁴4p levels of Fe IV are calculated using the CIV3 code of Hibbert and coworkers. Using the Hartree-Fock functions up to 3d orbitals we have also optimized 4s, 4p, 4d, 4f, 5s, 5p and 5d orbitals of which 4s and 4p are taken to be spectroscopic and the remaining orbitals represent corrections to the spectroscopic orbitals or the correlation effects. The J-dependent levels of 108 LS states are included in the calculation and the relativistic effects are accounted for via the Breit-Pauli operator. Configurations are chosen in two steps: (a) two promotions were allowed from the 3p, 3d, 4s and 4p subshells, using all the orbitals; and (b) selective promotions from the 3s subshell are included, but only to the 3s and 4s orbitals. The ab initio fine-structure levels are then fine tuned to reproduce observed energy levels as closely as possible, and the resulting wavefunctions are used to calculate oscillator strengths and transition rates for all possible E1 transitions. For many of these transitions, the present results show good agreement between the length and velocity forms while for some transitions, some large disagreements are found with other available results. The complete list of weighted oscillator strengths, transition rates, and line strengths for transitions among the fine structure levels of the three lowest configurations are presented in ascending order of wavelength.     

过渡金属元素中d和f电子行为的正电子湮没研究

采用双探头符合技术,大幅度地降低了正电子湮没辐射Doppler展宽谱的本底,使谱线的峰高与本底之比高于104,从谱线的高能端提取正电子与过渡金属原子中d或f电子湮没的信息.测量了Zr、Nb、Mo、Ag、Hf、Pt、Au等纯金属和单晶Si样品的符合Doppler展宽谱,并以单晶Si样品为参考作出了这些金属的商谱.结果表明:金属Zr、Nb、Mo、Ag的商谱随原子的4d电子数目的增多而升高;金属Hf、Pt、Au的商谱出现了双峰,其峰高均随原子序数的增加而升高.     

Analysis of the Ne- like 2p~53s,3p and3d configurations of Br XXVI

FollowingthefirstdemonstrationofsoftX-rayinNe-likeSe24 manyexperimentalandtheoreticalstudiesofthestructureofNe-likeionshavebeenreported.In1994NilsenandScofieldprovidedacriticalevaluationofthewavelengthsofallobserved3s-3plineswithlaserpropertiesforionsbetw…     

Transition probabilities for 5s-5p, 5p-5d, 4f-5d, and 5d-5f transitions in Ag-like ions with Z = 50-86

The wavelengths, electric dipole transition probabilities, and oscillator strengths are calculated for transitions between low-lying states (5s-5p, 5p-5d, 4f-5d, and 5d-5f) in the silver isoelectronic sequence (50 ? Z ? 86) using relativistic perturbation theory with a zero-approximation model potential. The results are compared with the corresponding data of the relativistic Hartree-Fock theory and the relativistic many-body perturbation theory. The results of these three theoretical approaches are compared with available experimental data for the level lifetimes. Possible reasons for some disagreements are discussed.     

离子辐照后4H-SiC晶体退火前后的光谱研究

分析了高能pb27 辐照预注入12C 的和未预注入12C 4H-SiC样品在,退火前后傅立叶变换红外光谱和拉曼散射光谱的变化.从傅立叶变换红外光谱可以知道,900℃以上的退火使损伤层发生显著恢复;在拉曼散射光谱中可以看到1200℃退火后有石墨相的存在.实验结果说明,高温退火有利于损伤的恢复,使注入到碳化硅中的碳原子发生聚集并引起相变.     

Breit-Pauli energy levels belonging to 2p, 2s2p, 2p, 2p3? configurations and all E1 transitions among these levels in Mg V

We present accurate oscillator strengths, line strengths and radiative rates for 1073 E1 transitions among the 86 levels belonging to 2s²2p⁴, 2s2p⁵, 2p⁶, and 2s²2p³(⁴S^o, ²D^o, ²P^o)3? configurations in Mg V. We have used 1s and 2s Hartree-Fock orbitals, re-optimized 2p on 2p³(²D^o)3s ³D^o and optimized 3s,3p,3d orbitals on real states. Sixteen additional orbitals up to 8d are optimized either as a correction to n = 3 physical orbitals or as a correlation orbital. A very large set of configurations including up to three electron promotions are used to account for all important correlation effects. All of the main five terms in the Breit-Pauli operator (except the orbit-orbit interaction) are included in order to account for the relativistic effects. Small adjustments to the diagonal elements of the Hamiltonian matrix are made to bring the calculated energies within a few cm⁻¹ of the corresponding NIST recommended data wherever available. The calculated oscillator strengths, line strengths, and radiative rates for almost all of the E1 transitions show excellent agreement with the corresponding MCDF results of Fischer. The recent results of Bhatia et al. are found to be consistently higher by 20-45%. The accuracy of the present calculation is considered to be better than the NIST accuracy ratings for various transitions.     

Weighted f-values, A-values, and line strengths for the E1 transitions among 3d, 3d4s, and 3d4p levels of Fe III

Weighted oscillator strengths, weighted radiative rates, and line strengths for all the E1 transitions between 285 fine-structure levels belonging to the 3d⁶, 3d⁵4s, and 3d⁵4p configurations of Fe III are presented, in ascending order of wavelength. Calculations have been undertaken using the general configuration interaction (CI) code CIV3. The large configuration set is constructed by allowing single and double replacements from any of 3d⁶, 3d⁵4s, 3d⁵4p, and 3d⁵4d configurations to nl orbitals with n?5,l?3 as well as 6p. Additional selective promotions from 3s and 3p subshells are also included in the CI expansions to incorporate the important correlation effects in the n=3 shell. Results of some strong transitions between levels of 3d⁶, 3d⁵4s, and 3d⁵4p configurations are also presented and compared with other available calculations. It is found that large disagreements occur in many transitions among the existing calculations.     

用于离子能谱测量的Thomson谱仪设计与数据处理技术

在设计可用于测量质子、n粒子以及其他重带电离子能谱的Thomson谱仪的过程中,研究了带电离子在谱仪电场和磁场作用下的运动轨迹,开发了相应的计算机辅助设计软件。CR39固体径迹探测器作为离子记录介质,离子径迹在记录面呈现抛物线带状分布,研究了由抛物线带状分布回推离子能谱的数据处理方法。     

用于光谱和能级寿命测量的控制及数据获取电子学系统

简要介绍了为高电离态原子光谱学实验研究装置研制的控制及数据获取电子学系统。该系统主要用于光谱和能级寿命的测量控制与数据获取。     

Systematic investigation of spectroscopic factors from (d,p) reactions for deuteron nuclear data evaluation

Spectroscopic factors for the (d,p) reactions on ¹²C, ²⁷Al, ⁴⁰Ca, and ⁵⁸Ni for incident deuteron energies up to 100 MeV were extracted systematically by fitting theoretical distorted wave Born approximation calculations to the existing experimental data. The extracted spectroscopic factors show similar incident energy dependence for all the target nuclei. An empirical expression describing the energy dependence has been deduced and implemented in a computational code system developed specially for deuteron-induced reactions. The calculation with the code system reproduces the measured ²⁷Al(d,p)²⁸Al cross sections in the incident energy range from the threshold to 20 MeV and the measured double-differential cross sections for (d,xp) reactions on ¹²C and ⁵⁸Ni at 56 and 100 MeV fairly well.     

Measurement of (d,p) and (d,α) differential cross-sections for N

The differential cross-sections for ¹⁴N(d,p₀)¹⁵N, ¹⁴N(d,p₁₊₂)¹⁵N, ¹⁴N(d,α₀)¹²C and ¹⁴N(d,α₁)¹²C have been measured in the energy range from 0.7 to 2.2 MeV at the laboratory angle of 150°. The obtained results are compared with data published in the literature. Discrepancies between new and previously acquired data are discussed. The cross-sections measured in the present work were uploaded to the IBANDL data base <http://www-nds.iaea.org/ibandl/>.     

Electron collisions with Fe-peak elements: Forbidden transitions between the low lying valence states 3d, 3d4s, and 3d4p of Fe III

Effective collision strengths are presented for the Fe-peak element Fe III at electron temperatures (T_e in degrees Kelvin) in the range 2 × 10³ to 1 × 10⁶. Forbidden transitions results are given between the 3d⁶, 3d⁵4s, and the 3d⁵4p manifolds applicable to the modeling of laboratory and astrophysical plasmas.     

Energies and E1, M1, E2, M2 transition rates for states of the 2s22p, 2s2p2, and 2p3 configurations in boron-like ions between N III and Zn XXVI

Energies, E1, M1, E2, M2 transition rates, line strengths, oscillator strengths, and lifetimes from relativistic configuration interaction calculations are reported for the states of the (1s²)2s²2p, 2s2p², and 2p³ configurations in all boron-like ions between N III and Zn XXVI. Valence, core–valence, and core–core correlation effects were accounted for through single–double multireference (SD-MR) expansions to increasing sets of active orbitals.     

Modern applications of high energy ion beams: from “single-event burnout” to human eye cancer treatment

Energetic ion beams, originally the domain of nuclear physics, become increasingly important tools in many other fields of research and development. The choice of ion species and ion energy allows an enormously wide variation of the penetration depth and of the amount of the electronic stopping power. These features are utilized to modify or damage materials and living tissues in a specific way. Materials modification with energetic ion beams is one of the central aims of research and development at the ion beam laboratory, ISL-Berlin, a center for ion-beam applications at the Hahn-Meitner-Institut Berlin. In particular, energetic protons will be used for eye cancer treatment. Selected topics such as the “single-event burnout” of high power diodes and the eye cancer therapy setup will be presented in detail.     

Theoretical study of the interaction between hydrogen and 4d alloying atom in nickel

In order to investigate the tritium behaviors in Hastelloy N alloy in molten salt reactor,first-principles calculations are used to study the interaction between hydrogen and 4d transition metal alloying atom in nickelbased alloy.The interaction energies between 4d elements and H are calculated.Atomic size effects and electron distribution effects are analyzed.The hydrogen-4d interactions are compared with the hydrogen-3d interactions calculated in our previous work.     

Resolution enhancement of the 3He(d,p)4He resonance for profiling helium in solids

The use of nuclear resonances techniques for characterizing the distribution and lattice location of implanted atoms in metals is a direct and, in principle, simple method for studying helium and hydrogen gas in CTR first wall materials. However, the reaction ³He(d,p)⁴He, has a broad (350 keV) half-width in the resonance yield curve. When using a deuteron beam, under normal probing conditions, to measure helium distributions in metals, a rather low stopping power results in limited resolution of about 3 μm. In many cases resolution of a few thousand angstroms or better is necessary. We have experimentally examined two resolution enhancement methods and reported the results in a previous article. The present paper will review those results and examine limitations of resolution enhancement that are obtainable through geometrical and mathematical techniques.