Spectra and oscillator strengths of 3p63d9--3p53d10 and 3p63d9--3p63d84p transitions for cobalt-like Sn23+ ion

This paper calculates the spectra and oscillator strengths for highly ionized cobalt-like Sn23+ ions 3p63d9 3p53d10,3p63d9 3p63d84p transitions by using a multi-configuration self-consistent field method program together with the proposed fitting formula.The calculations have a good agreement with observations.     

Lifetime of levels belonging to the 3p54p configuration of Ar(I)

The lifetimes of nine levels of Ar(I) belonging to the 3p⁵4p configuration have been measured by the delayed coincidence method, with errors in the range from 4 to 7%. The results are compared with other experimental values and with theoretical calculations using jK coupling and intermediate coupling. From cascade components of the 4p levels, decay lifetime values for some levels belonging to the 3p⁵3d and 3p⁵5s configurations have been inferred.     

Oscillator strengths for 3dn4s → 3dn4p transitions in the iron series

The observed oscillator strengths for the 3dⁿ4s → 3dⁿ4p transitions in the iron series show anomalous behaviour for Cr and Mn : the former is exceedingly small whereas the latter is unusually large.Theoretical Hartree-Fock gf-values are reported and a considerable discrepancy with experimental values is noted for Cr. The effect of the interaction of 3dⁿ4p with 3d^n?14s4p is studied using a fixed core, multi-configuration Hartree-Fock approximation. This interaction does not improve significantly the agreement with observed values.     

Magnetic ordering of a d1 compound: VF4

Magnetic susceptibility and nuclear magnetic resonance above and below the ordering temperature show that VF₄ is an $\text{S =}\text{1}\text{2}$, 3d¹ canted antiferromagnet with a transition temperature near 28°K and a canting angle of ～ .02 rad. The compound is not an example of a proposed nonmagnetic singlet ground state of resonating covalent bonds.     

Oscillator strengths for selected 3dn4s−3dn4p transitions of the iron-group elements

Absolute transition probabilities are calculated for selected 3dⁿ4s?3dⁿ4p transitions of the iron-group elements; configuration interaction effevts are taken into account. Comparisons with Hartree-Fock and multi-configuration Hartree-Fock results and with experimental data show that the scaled Thomas-Fermi method for calculation radial wave functions is useful procedure.     

Laser photoelectron spectrometry of Sc− and Y−: A determination of the order of electron filling in transition-metal anions

The photoelectron spectra of Sc^? and Y^? have been obtained in a crossed ion- and laser-beam experiment. Analysis of the Sc^? spectrum yields two bound terms of 3d4s² 4p configuration (¹D⁰ and ³D⁰), with EA(Sc) = 0.189 ± 0.020 eV and an excited-state binding energy of 0.042 ± 0.020 eV. Similarly, the (4d5s² 5p) ¹D⁰ ground state of Y^?is bound by 0.308±0.012eV and a (4d5s²5P)³D⁰ excited term is bound by 0.165± 0.025 eV. With the determination of the bound electronic configuration of Sc^? as 3d4s²4p, the order of filling of electron shells of the first transition series negative ions is found to be 4s²4p, 3d4s²4p, followed by 3d^k4s² (k = 3,4,…, 10).     

Nb XIII离子3d94s2, 3d94s4p, 3d94p2 组态能级结构与跃迁的理论研究

用准相对论Hartree-Fock方法对Nb XIII离子二电子激发组态3d⁹4s², 3d⁹4s4p, 3d⁹4p² 的能级结构做了全面系统的理论计算研究.在对已有研究结果分析的基础上, 运用最小二乘方法对径向积分参数进行了优化计算, 得到了与这些组态有关的电偶极允许跃迁的谱线波长和跃迁概率.计算结果与最新的实验值做了对比分析, 表明本文计算结果是准确的. 研究发现, 波长40.92 nm的谱线, 属于3d⁹4s(¹D)4p²F_7/2–3d⁹ (²D)4s^{2 2}D_5/2 的跃迁谱线, 而不属于3d⁹4s (¹D)4p⁴D_7/2–3d⁹(²D)4s^{2 2}D_5/2 的跃迁谱线, 即上谱项能级为²F_7/2, 而不是⁴D_7/2. 关键词： Nb XIII离子 二电子激发组态 谱线波长 跃迁概率     

Excited-state absorption spectroscopy from the 3d9 4s relaxed excited state of Cu+ in KBr and NaBr

Data on the low temperature optical absorption from the optically-pumped relaxed excited state 3d⁹ 4s of Cu⁺, substitutional in KBr, are here reported for the first time. These results are discussed and it is suggested that the absorption peaks at higher energies are due to transitions from the 3d⁹ 4s to states of the conduction band continuum.     

The establishment of the 5d23F and 1S levels in Ba I

The metastable 5d²³F levels in Ba I have been established by observations in the extra-photographic infrared. The 5d²¹S level has been established in connection with identifications of laser lines observed by Cahuzac and lines observed by selective excitation.     

The electronic structure of CuCl: An “ab initio” Hartree-Fock SCF-MO study of the CuCl43− cluster

Results from restricted Hartree-Fock SCF-MO calculations on the CuCl₄^3? cluster occurring in solid CuCl are reported. The chemical bonding is discussed on the basis of a population analysis of the ground state orbitals. Calculations on the first ionized states show the Cu 3d electrons to be less tightly bound than the Cl 3p electrons in contrast to Koopmans' theorem predictions and in agreement with experiment. The high degree of localization of the 3d hole orbitals obtained is in conflict with earlier estimates of d-bond covalency. It is suggested that the “Ham effect” rather than covalency is responsible for the reduced spin orbit splitting that can be deduced from the observed exciton absorption. The potential surface for a Cu⁺ ion moving in the field of neighbouring Cl^? ions, has been determined from calculations on the CuCl₄^3? cluster in which the metal ion has been displaced towards a face, an edge or a vertex of the surrounding tetrahedron. The vibration frequency and the activation energy for the diffusion of Cu⁺ ions obtained are in fair agreement with the experimental data. These results support the viewpoint that the anomalous change in scattering intensity with temperature observed in X-ray and neutron diffraction studies is due to the presence of a substantial fraction of the Cu⁺ ions on interstitial lattice sites.     

Paramagnetic Ru5+ and Ru3+ centers in TiO2:Ru

Paramagnetic resonance on TiO₂ single crystals doped with ruthenium have shown the presence of both Ru⁵⁺(4d³) and Ru³⁺(4d⁵) in oxygen octahedral coordination.     

Magneto-optical study of the 5ƒ2 → 5ƒ16d1 transition in UO2

High field Faraday rotation and magnetic circular dichroism measurements in the energy range between 1.4 and 5.4eV are reported for UO₂. The measurements are compared with two modified atomic models for the 5?² → 5?¹6d¹ transition using LS- and jj-coupling, respectively. Excellent agreement between theory and experiment is found only for a jj-coupling treatment of the final state.The Faraday rotation for magnetic saturation is estimated to be 3 × 10⁶ deg cm^?1 at 4.5 eV.     

Bestimmung der Lebensdauer des 3d 9 4s 4p 4 P 3/2-Terms im Cu I-Spektrum mit optischer Doppelresonanz

The lifetime of the 3d ⁹ 4s 4p ⁴ P _3/2 state of Cu has been determined with optical double resonance by observation of radiofrequency transitions ΔF=0, Δm _F =±1 between hfs-Zeeman levels of the stable odd isotopes. The result is τ(3d ⁹ 4s 4p ⁴ P _3/2, Cu)=3.18(16)·10^?7 sec.     

Nature of optical properties of GdFe3(BO3)4 and GdFe2.1Ga0.9(BO3)4 crystals and other 3d5 antiferromagnets

Influence of the partial substitution of paramagnetic Fe³⁺ ions by diamagnetic Ga³⁺ ions in the trigonal crystal GdFe₃ (BO₃)₄ on its optical and magnetic properties is studied and discussed in connection with problems common for all antiferromagnets containing 3d ⁵ ions. Polarized optical absorption spectra and linear birefringence of GdFe₃ (BO₃)₄ and GdFe_2.1Ga_0.9 (BO₃)₄ single crystals have been measured in the temperature range 85–293 K. Specific heat temperature dependence (2–300 K) and structure of GdFe_2.1Ga_0.9 (BO₃)₄ crystal have been also studied. As a result of substitution of 30% Fe to Ga the Neel temperature diminishes from 38 till 16 K, the strong absorption band edge shifts on 860 cm^-1 (0.11 eV) to higher energy and the d-d transitions intensity decreases substantially larger than the Fe concentration does. Strong absorption band edge is shown to be due to Mott-Hubbard transitions. Correlation between position of the strong absorption band edge and the Neel temperature of antiferromagnets has been revealed. Properties of the doubly forbidden d-d transitions in the studied crystals and in other antiferromagnets are explained within the framework of the model of the exchange-vibronic pair absorption, which is theoretically analyzed in detail. The model permitted us to determine the connection between parameters of d-d absorption bands (intensity, width and their temperature dependences), on the one hand, and the exchange, spin-orbit and electron-lattice interactions, on the other hand.     

Spectroscopic investigations and configuration-interaction-assisted crystal field analysis of Pr in YPO4 single crystal

An optical study of a Y_0.99Pr_0.01PO₄ single crystal is presented. Measurements of optical absorption, excitation, and emission by selective excitation into ¹D₂, ³P₀ and ³P₁, at different temperatures between 20 and 295 K, are described. A detailed account of the line assignments is given for absorption in the 4300-23 000 cm⁻¹ spectral range, and for emission in the 6400-23 000 cm⁻¹ range. The lifetimes of the emitting levels are determined. Vibronic sidebands accompanying absorption, emission and excitation spectra are reported. The decay processes of the ³P₁, ³P₀ and ¹D₂ levels are discussed. The aim of this study is a test of the configuration-interaction-assisted crystal field analysis as well as the accurate experimental determination of the energy level scheme. It was reported previously that the introduction of configuration interaction between the ground 4f² configuration with the excited 4f6p configuration always resulted in a decrease (≈50-60%) in the standard deviations between the observed and calculated energy levels. In the present work the 4f5d configuration is included as well. The crystal field is analysed in the theoretical D_2d site symmetry with and without configuration interaction. The results with 4f², 4f²+4f5d, 4f²+4f6p and 4f²+4f5d+4f6p are given. The calculation on the basis of the 315 (4f²+4f5d+4f6p) levels gives the best overall standard deviation lowering it by 75% with regard to the calculation on the 91 4f² levels only.     

ESR assessment of 3d7 transition metal impurity states in GaP,GaAs and InP

Photo-sensitive electron spin resonance of the 3d⁷-ions Fe⁺, Co²⁺, Ni³⁺ has been detected and analysed in GaP, GaAs and InP. For GaP : Ni³⁺, hyperfine interaction with the four nearest P³¹-ligands could be resolved.     

Perturbation study via rotational-resolved spectrum in the triplet band d3Δ-a3∏(2, 1) of CO

The triplet band d³Δ-a³∏ (2, 1) of the CO molecule in the near infrared region of 12350--12850cm^-1 has been observed and analysed by taking into account the perturbation interaction between the d³Δ(v = 2) and a³∏ (v = 9) states. The most perturbed lines and most precise perturbation parameters, \alpha₂ and \beta₂, and electronic perturbation constants,\xi _\e and \eta _\e , for the d³Δ (v= 2) and ³∏ (v = 9) states have been obtained.     

Structure electronique des oxydes de cobalt CoO et Co3O4

The total density of occupied states in the valence band of CoO and Co₃O₄ is determined by XPS and UPS. From variations of excitation probability of the bands, the 4 e V wide O2_p band is shown to be located around 5 eV for both oxides, while structures obtained from photoionisation of the localized 3d band spread over 10 eV range below the Fermi level overlapping with O2_p band. The 3d peaks located at binding energy <3 eV correspond to the calculated energy of the d_n ?1 manifold final state in the octahedral and tetrahedral crystal field of CoO and Co₃O₄. The 3d levels at higher binding energy are shown to occur from configuration interaction in both final and initial states. These last peaks are higher in intensity for CoO relative to Co₃O₄. A superior limit for the width of the 3d initial band in a one electron energy diagram is given to be <3 eV. This value associated to the Coulomb correlation energy measured equal to ~3 eV. This value associated to the Coulomb correlation energy measured equal to ~3 eV from shake-up and Auger energy confirms the Mott insulator nature of CoO.     

流体静压下AlAs合金化的GaAs中Cr2+(3d4)杂质态的理论研究

本文将一个自旋极化的紧束缚格林函数方法发展到用于流体静压和合金下GaAs:Cr²⁺(3d⁴)杂质态的研究。文中给出了GaAs:Cr²⁺系统⁵E激发态和⁵T₂基态受主能级随压力和AlAs合金成份的变化趋势。理论证明了在一定的压力和Al成份下,⁵E激发态将从导带底进入带隙,原在通常条件下观察不到的⁵E→⁵T_关键词：     

Configuration mixing and crystal-field splitting of Cr2+ in CdS

The effect of interaction of excited configurations 3d³4s, 3d³4p and 3d³4d with the ground 3d⁴ configuration on the crystal field splitting (E- T₂) of the tetrahedral Cr²⁺ ion in CdS has been studied by a rigorous method in which the energy matrix constructed in a basis of states belonging to both the ground and excited configurations has been directly diagonalised. Such a fairly rigorous treatment yield surprising results and interesting conclusions. Even though the calculation is based on an ionic model of the crystal field, it is found that inclusion of excited configurations accounts for the entire crystal field splitting observed experimentally in this particular case of Cr²⁺ in CdS. The configuration mixing in our treatment yields for the crystal field splitting a result few times greater than that found when the calculation is confined within the ground configuration only. Furthermore, the present investigation indicates that the second order perturbation method used in the earlier treatment was quite inadequate in the case of Cr²⁺ in CdS.