One-electron spectrum of Lu2+: Relativistic energies,transition probabilities and dipole polarizability

Calculations are reported of relativistic model-potential ionization energies and transition probabilities in the one-electron spectrum of doubly ionized lutetium. The approach employed includes both valence-core electron exchange and correlation. The influence of polarization of the core by the valence electron on ionization energies and transition probabilities has been studied. Strong cancellation effects, similar to those found previously for the Yb(II) spectrum, have been found for higher transitions of the principal series. Energies are predicted for some states that have not yet been determined experimentally. Computed oscillator strengths for the principal series are employed to obtain a tentative value for the static dipole polarizability of the doubly-ionized lutetium ground state … 4f¹⁴6s²S_{$\text{1}\text{2}$}.     

Transition energies, wavelengths, oscillator strengths and transition probabilities between 1s, 1sns and 1snp (2?n?9) states for He-like Silicon

Multiconfiguration Hartree-Fock calculations with Breit-Pauli relativistic corrections are reported for electric dipole transition (E1) energies, wavelengths, weighted oscillator strengths and transition probabilities between all of the 1s², 1sns and 1snp (2?n?9) states for He-like silicon. The results are found to compare very well with available other results except Δn=0 due to differences in the calculated excitation energies.     

Relativistic energies and transition probabilities for some highly excited levels in singly ionized indium

For some excited levels (n?8), the energies, wavelengths, oscillator strengths and transition probabilities calculations in singly ionized indium have been calculated within the framework of multiconfiguration Hartree-Fock approximation with relativistic corrections (Breit-Pauli Hamiltonian). The wavefunctions and some relativistic corrections have been obtained using MCHF-BP atomic package. Comparisons with other calculations and experiments are presented.     

Electric dipole transitions for highly excited states in helium-like sulphur

We have calculated relativistic energies, weighted oscillator strengths and transition probabilities for electric dipole (E1) transitions among the terms belonging to 1snl (n?9, l?3) configurations in helium-like sulphur. The calculations are based upon the multiconfiguration Hartree-Fock method within the framework of Breit-Pauli relativistic corrections. Our calculated values are also compared with other experimental and theoretical results.     

Spectra of heliumlike carbon,aluminium and argon under strongly coupled plasma

Spectral line positions for the highly stripped helium like carbon, aluminium and argon embedded in intense plasma environments have been calculated theoretically to compare with the existing data available from laser plasma experiments. The changes in the ionization potentials for such ions have been determined and the excitation energies, oscillator strengths and transition probabilities for the transitions 1s^{2 1}S → 1snp ¹P (n=2-5) have been evaluated for the diagnostic determination of such plasmas. The ion sphere (IS) model was used for estimating the effect of strongly coupled plasma on the ions within the non-relativistic as well as the relativistic framework. Time dependent perturbation theory has been applied for obtaining the linear response properties of the ions in the non-relativistic approximation. The effects of the plasma environment on such properties of the ions under the Debye screening model with suitable cut off radii have also been considered for comparing the data with those obtained from the IS model of the plasma.     

Electron spectroscopy using excited atoms and photons IV. Penning ionization of ethylene

Using helium metastable atoms (2¹S, 2³S), the Penning ionization of C₂H₄ has been studied using a high resolution electrostatic electron analyzer. The Franck—Condon envelope for the ground state of C₂H₄⁺ (X²B_3u) is found to be the same for He* (2³S) Penning ionization and 584 Å photoionization. The ΔE shift values and the relative electronic transition probabilities are reported for four ionic states. Unusually large differences have been found for the relative electronic transition probabilities for Penning ionization and photoionization.     

Theoretical study on the 1s22s-1s2 np transitions for Ni25+ ion

The transition energies, wavelengths and oscillator strengths for the 1s²2s-1s² np (n ? 9) transitions of Ni²⁵⁺ ion are calculated. In calculation of the energies, we not only take account of the firstorder corrections from relativistic and mass-polarization effects, but also estimate the higher-order relativistic contribution and QED correction by introducing the effective nuclear charge. The results agree with experimental data available in literature satisfactorily. Grotrian diagram showing these transitions is given.     

相对论效应对类锂离子能级结构及辐射跃迁性质的影响

利用基于多组态Dirac-Hartree-Fock(MCDHF) 理论方法的相对论原子结构计算程序包GRASP2K, 细致计算了中性锂原子、类锂Be⁺, C³⁺, O⁵⁺, Ne⁷⁺, Ar¹⁵⁺, Fe²³⁺, Mo³⁹⁺, W⁷¹⁺及U^{89 +} 离子基组态及较低的激发组态1s²nl (n = 2---4, l =s,p,d,f) 的精细结构能级, 以及各能级间发生电偶极(E1) 自发辐射跃迁的能量、概率及振子强度. 同时, 在非相对论极限下, 计算了其相关原子参数. 通过对相对论及非相对论计算结果的比较, 系统研究了相对论效应对类锂等电子系列离子能级结构及E1跃迁性质的影响, 揭示了随原子核电荷数Z变化时, 跃迁能、振子强度强烈依赖于量子数n, l, j变化的规律; 同时, 目前的计算结果与其他已有的理论计算及实验测量结果进行了比较.     

Fine-structure energy levels, oscillator strengths and lifetimes of chlorine-like chromium

We have done relativistic calculations for the evaluation of energy levels, oscillator strengths, transition probabilities and lifetimes for Cr VIII ion. Use has been made of configuration interaction technique by including Briet-Pauli approximation. The energies of various levels from the ground state to excited levels of 3s3p⁶, 3s²3p⁴3d, 3s²3p⁴4s, 3s²3p⁴4d of Cr VIII are given in LSJ coupling scheme after fine-tuning and are compared with the experimental results compiled in the NIST Data Base. Many new lines have been predicted which have not appeared so far in the NIST Data.     

Radiative transitions in highly ionised silicon-like ions

Transition energies, oscillator strengths and transition probability values for radiative transitions have been calculated for the highly ionised atoms of Si isoelectronic sequence from Mn¹¹⁺ to Kr²²⁺ for the singly excited states up to principal quantum number n = 7. Time-dependent coupled Hartree-Fock (TDCHF) theory has been used to estimate such transition properties. Most of the results for the oscillator strengths and transition probabilities are new. Transition energies agree reasonably well with available spectroscopic values. Received 25 January 2000 and Received in final form 24 October 2000     

The reaction 35Cl(n,γ)36Cl studied with non-polarized and polarized thermal neutrons

The γ-radiation following capture of non-polarized and polarized thermal neutrons in ³⁵Cl has been investigated. Of the 420 γ-rays ascribed to the ³⁵Cl(n,γ)³⁶Cl reaction, 236 have been placed in a ³⁶Cl decay scheme. The branching ratios and the excitation energies (with 0.04–0.9 keV errors) of 72 bound states have been determined. Unambiguous spin assignments are given for 11 levels. The multipole mixing ratios for some primary γ-ray transitions have been determined. There exists a significant correlation between (d, p) stripping strengths and (n, γ) reduced primary transition probabilities for transitions to l_n(d, p) = 0 levels.     

Spectroscopy of 32P (II)

Spins, parities and transition probabilities of levels in ³²P at E_x > 3.5 MeV have been determined with the ²⁹Si(α, pγ)³²P reaction at bombarding energies of E_α = 12.80, 12.93 and 16.30 MeV. Proton-gamma angular correlation experiments and DSA lifetime measurements lead to six unambiguous spin assignments and to many spin limitations. The measured mixing and branching ratios yield many transition strengths for dipole and electric quadrupole transitions. Five, sofar unknown, energy levels are reported. A doublet at 4.03 MeV excitation energy and a high-spin state (E_x = 4.27 MeV; J^π = 5^?) were observed. Shell-model predictions have been compared to the present experimental results.     

Allowed and forbiddenn=2-2 transitions of highly ionised titanium

Relativistic intermediate-coupling wavefunctions are used to evaluate transition energies, line strengths and transition probabilities for all allowed and forbiddenn=2-2 transitions for beryllium-like titanium ion. We have shown that to achieve a better than 1% agreement between theory and experiment for transition energies between then=2-2 levels it is not sufficient to use the three-configuration basis composed of 2s ², 2s2p and 2p ².     

Relativistic calculations of 3s2 1S0-3s3p 1P1 and 3s2 1S0-3s3p 3P1,2 transition probabilities in the Mg isoelectronic sequence

Using the multi-configuration Dirac-Fock self-consistent field method and the relativistic configuration-interaction method,calculations of transition energies,oscillator strengths and rates are performed for the 3s 2 1 S 0-3s3p 1 P 1 spinallowed transition,3s 2 1 S 0-3s3p 3 P 1,2 intercombination and magnetic quadrupole transition in the Mg isoelectronic sequence(Mg I,Al II,Si III,P IV and S V).Electron correlations are treated adequately,including intravalence electron correlations.The influence of the Breit interaction on oscillator strengths and transition energies are investigated.Quantum electrodynamics corrections are added as corrections.The calculation results are found to be in good agreement with the experimental data and other theoretical calculations.     

New atomic data for Kr XXXV useful in fusion plasma

Energy levels and emission line wavelengths of high-Z materials are useful for impurity diagnostics due to their potential application in the next generation fusion devices.For this purpose,we have calculated the fine structural energies of the 67 levels belonging to the 1s 2,1s2l,1s3l,1s4l,1s5l,and 1s6l configurations of Kr XXXV using GRASP(general purpose relativistic atomic structure package) code.Additionally,we have reported the transition probabilities,oscillator strengths,line strengths,and transition wavelengths for some electric dipole(E1) transitions among these levels.We predict new energy levels and radiative rates,which have not been reported experimentally or theoretically,forming the basis for future experimental work.     

DasKLL- Auger-Spektrum von Chlor

TheKLL Auger spectrum of chlorine in CCl₄ has been investigated with an electrostatic energy analyzer. The ionization in theK shell of chlorine was caused by electron impact. Absolute energies and relative intensities of transitionsKL ₁ L ₁(¹ S,KL ₁ L _2,3(¹ P),KL ₁ L _2,3(³ P) andKL _2,3 L _2,3(¹ D) have been determined. Via the width of theK level of chlorine also experimental values of absolute transition probabilities have been calculated. While the relative intensities deviate strongly from theoretical values, the absolute transition probabilities agree better with theoretical values, especially with those calculated byRubenstein. — In an appendix the natural line widths of theKLL components of argon have been calculated theoretically.     

类铍离子磁四极M2 2s2 1S0—2s2p3P2 (Z=10—103)禁戒跃迁

利用全相对论多组态Dirac-Fock方法系统地计算了高离化类铍离子的磁四极M2 2s²¹S₀—2s2p³P₂ (Z=10—103)自旋禁戒跃迁的能级间隔、跃迁概率和振子强度，计算中考虑了重要核的有限体积效应，Breit修正和QED修正，所得结果和最近的实验数据以及理论值进行了比较，结果表明：高原子序数的高电荷离子(Z≥70)磁四极M2自旋禁戒跃迁几乎可以和中性原子的光学允许跃迁相比拟，不仅在天体等离子体中，在ICF和MCF高温激光等离子体中，磁四极自旋禁戒跃迁和其他自旋禁戒跃迁（磁偶极、电四极）一样不容忽视，在双电子复合、不透明度、自由程等理论计算中应该考虑其影响. 关键词： 磁四极M2 能级间隔 跃迁概率 振子强度     

Effects of dirac sea on giant resonance states

There are two approximations in relativistic models which keep the continuity equation of the baryon current without renormalization of the divergence. One is the no-free-term approximation (NFA) which neglects the divergent terms, but keeps the Pauli blocking terms coming from nucleon-antinucleon excitations in the RPA correlation functions. The other is the no-sea approximation (NSA) where antiparticle states are assumed to be empty with negative energies. It is shown that both approximations formally satisfy the Ikeda sum rule and the RPA theorem for the β_? and β₊ transition strengths also, but that the NFA requires negative strengths in the positive excitation energy region, while the NSA requires positive strengths in the negative excitation energy region, as a price of neglecting the renormalization of the divergence.     

Spin-polarized relativistic calculations on highly ionized molybdenum

The energies of K_α X-ray satellite lines of molybdenum ionized to different degrees in the L shell with closed and open outer shells (n=3,4 and 5) are reported in this work. The calculations have been carried out using Xα method with spin-polarized single configuration relativistic Dirac-Fock wavefunctions. Calculations have also been carried out with un-polarized relativistic wavefunctions. The effect of relativistic spin exchange potential on the total energies of the various states ionized to different degrees in the inner and outer shells are analyzed. As the transition assignments in the spin-polarized treatment of atomic orbitals take into account the spin orientations of the electrons in the initial and final states, the present calculations elucidate the significance of this technique in giving unique spin-dependent transition assignments to experimental energies.     

类钾离子4s 2S1/2─3d 2D3/2电四极矩E2光谱跃迁的理论研究

采用全相对论量子力学GRASP²程序,广义平均能级EAL模型,在核的有限体积效应,Breit和QED效应的高阶扰动基础上,考虑到原子实的极化,系统地计算了高剥离类钾离子4s ²S_1/2─3d ²D_3/2电四极矩E2光谱跃迁的能级间隔,跃迁概率和振子强度,结果表明：考虑原子实极化效应后,计算的精细能级结构间隔与实验数据之间的系统误差基本消除,其跃迁概率和振子强度属首次报道. 关键词： 高剥离态 能级间隔 振子强度