Theoretical oscillator strengths for some transitions in Si(II), Ge(II), Sn(II) and Pb(II) spectra

Calculations are reported of non-relativistic and relativistic oscillator strengths for the principal, sharp and diffuse series as well as some lifetimes in the spectra of singly-ionized silicon, germanium, tin and lead. The radial integrals were computed by employing the wave functions obtained from a semiempirical approach which included exchange effects (the semiempirical X$\text{α}$ method). Good agreement was obtained with available experimental and theoretical data. A comparison between non-relativistic and relativistic oscillator strengths confirms the importance of the spin-orbit interaction of the optical electron, as well as other relativistic effects for the oscillator strengths, even for the spectra of moderately heavy ions. Some systematic trends in the calculated oscillator strengths and line-strength ratios were investigated along the spectral series, as well as along the sequence of homologous ions.     

Relativistic oscillator strengths for some transitions in Cu(I), Ag(I) and Au(I)

Relativistic oscillator strengths have been calculated for transitions in the principal, sharp and diffuse series of Cu(I), Ag(I) and Au(I) spectra. The computations have been performed by employing a semiempirical method which includes exchange and core-polarization effects. A comparison is presented for the calculated ?_ik values with experimental and other theoretical data. The influence of core-polarization effects on oscillator strengths is discussed.     

Theoretical oscillator strengths for the NI and OI resonance transitions

We report results from the first many-body calculations of the important oscillator strengths of the resonance lines NI $\text{1s}{}^2\text{2s}{}^2\text{2p}{}^3{}^4\text{S°?is}{}^2\text{2s}{}^2\text{2p}{}^2\text{3s}{}^4\text{P(λ=1200}\text{A}\text{?}\text{), 1s}{}^2\text{p}{}^2\text{3d}{}^4\text{P(λ=953}\text{A}\text{?}\text{)}$ and OI $\text{1s}{}^2\text{2s}{}^2\text{2s}{}^2\text{2p}{}^4{}^3\text{P ?1s}{}^2\text{2s}{}^2\text{2p}{}^3\text{3s}{}^3\text{S°(λ = 1304}\text{A}\text{?}\text{)}$. Our values are: $\text{?(1200)=0·271; ?(1304)=0·047; ?(953)= ·082}$. The first two are in excellent agreement with recent lifetime and absorption measurements and thus the existing discrepancy between theory and experiment is resolved. The third number constitutes the only available result for this transition.     

Theoretical ionization energies and oscillator strengths for carbon

Frozen core Hartree-Fock wave functions have been calculated for 98 excited s-, p- and d-levels of C(I), and employed to calculate electric dipole oscillator strengths for all allowed transitions between these levels. The energy levels generally agree with observations to within 1.3% and the length and velocity forms of the calculated л-values agree well except for very weak transitions.     

Theoretical term energies and oscillator strengths for carbon

Thomas-Fermi-Hartree-Fock wave functions have been calculated for nl-terms of carbon C(I) (n≤10 and l≤3) and employed to calculate electric dipole oscillator strengths for all allowed transitions between these terms. The dipole length and velocity form of the calculated f-values agree well with the available measurements.     

Experimental investigations of oscillator strengths for ultraviolet transitions in LaII

f-values for ultraviolet transitions from nine excited levels in LaII have been deduced by a combination of lifetime and branching ratio measurements using time-resolved laser spectroscopy and the emission spectrum from a hollow cathode lamp. Part of the present results is compared with previous results. Received 10 February 1999 and Received in final form 22 April 1999     

Optical oscillator strengths for Be II and B III

A simple two-parameter analytic potential adjusted so as to produce the experimental energy levels is used to generate wave functions for the ground and excited states of the ions Be II and B III. Using these wave functions we calculate optical oscillator strengths for various excitations from the 1s ²2s(² S) ground state. The results are compared to experiment and other calculations.     

XPS Spectra of organometallic phenyl compounds of P,As, Sb and Bi

XPS spectra of 54 organometallic compounds of group V elements with various coordinations are measured in the solid state. Core level binding energy data for the various atoms present in the molecules are given.     

Theoretical and experimental determinations of cesium oscillator strengths

The oscillator strengths of the cesium atom have been calculated theoretically using a semi-empirical construction of the effective potential acting on the valence electron. The results are compared with those deduced from an experimental determination in a quiescent cesium plasma.     

Thermoelectric and topological properties of half-Heusler compounds ZrIrX(As,Sb, Bi)

The strain dependent electronic structures, thermoelectric and topological properties of the half-Heusler compounds ZrIrX(X=As, Sb, Bi) are investigated by the first-principle calculations. At the equilibrium lattice constants, all the three compounds are trivial insulators and good thermoelectric materials with the Seebeck coefficient S and the power factor over relaxation time $S^2\sigma /\tau$ as large as 1180 (μV/K) and 4.1 (${10}^{11}W{m}^{?1}{K}^{?2}{s}^{?1}$), respectively. The compressive strain enhances the band gap, while the tensile strain decreases the band gap. At some specific tensile strains, the compounds become Dirac-semimetals, with the s-type band ${\mathrm{\Gamma }}_6$ below p-type band ${\mathrm{\Gamma }}_8$, in the cubic phase. When we compress the a(b)-axis and elongate the c-axis of the compounds, they become the type-I Weyl semimetals. For ZrIrAs, the eight Weyl-Points (WPS) locate at (± K_x, 0, ± K_z), (0, ± K_y, ± K_z), ${\mathrm{K}}_x={\mathrm{K}}_y=0.008{\mathrm{\AA }}^{?1}$, ${\mathrm{K}}_z=0.043{\mathrm{\AA }}^{?1}$.     

Differential oscillator strengths and dipole polarizabilities for transitions of the helium sequence

The dipole radial integral for an initial discrete 1s state and a final continuum state has been calculated under the screened hydrogenic model. In this model, single-electron hydrogenic wave functions are employed and the initial and the final states are treated by two different effective-charge parameters. Numerical values of differential oscillator strengths for transitions from 1s 21S to the continuum for the helium sequence ions are obtained. Also calculated are the dipole polarizabilities, which are found to be in excellent agreement with the results of other authors.     

Equilibrium diagrams for some AB3 (A=Sb,Bi, As and B=Cl,Br, I) compounds

Summary Equilibrium diagrams for some of the binary V–VII group semiconducting compounds were determined using regular and ideal solution theories. The calculated phase boundaries approximate the experimental curves.

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Riassunto Diagrammi all'equilibrio per qualcuno dei composti semiconduttori del gruppo binario V–VII sono stati determinati usando teorie per soluzioni regolari e ideali. I confini di fase calcolati approssimano le curve sperimentali.

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Резюме Определяются равновесные диаграммы для некоторых бинарных полупроводниковых соединений (V–VII группы), исполъзуя теории регулярных и идеальных растворов. Вычисленные фазовые границы аппроксимируют эксперменталъные кривые.

     

Calculation of oscillator strengths for P III,S IV,Cl V,and Ar VI

We use an analytic potential model adjusted to experimental energy levels to generate wave functions for the valence and excited states of the isoelectronic ions P III, S IV, Cl V, and Ar VI of the aluminum sequence. Using these wave functions in conjuction with the Born approximation and the LS-coupling scheme, we calculate optical oscillator strengths for various excitations of the valence electron. Good agreement is obtained with experimental and theoretical data.     

Theoretical studies of isotope shifts,hyperfine structures and oscillator strengths in transitions between low-lying levels in O I

Multiconfiguration Hartree-Fock (MCHF) and configuration interaction (CI) calculations have been performed for the low-lying levels 2p^{4 3}P, 2p³(⁴S⁰)3s ^3,5S⁰ and 2p³(⁴S⁰)3p ^3,5P⁰ of neutral oxygen. Different cancellation effects on the specific mass shift, on the electronic contributions to hyperfine interaction constants and on the length and velocity forms of oscillator strengths are illustrated. The final CI values are compared with experimental values and, when available, with values from other theories.     

Photodetachment of some atomic negative ions: P−, As−, Sb−, Bi−, Te−, Cr−, Ni−

The photodetachment cross sections have been measured in the photon energy range between 0.5 eV and 3 eV in a crossed beam experiment using a conventional light source.     

Stimulated changes in Bi(Sb)/As2S3 nanolayered structures

Investigations of a-Se/As₂S₃-type chalcogenide nanomultilayers (NML) were extended towards the metal-containing Bi(Sb)/As₂S₃ structures. It was shown that essential changes of optical parameters (transmission, refraction and reflection) and of the electrical conductivity occur due to the interdiffusion stimulated by direct heating or by the influence of the intensive laser beam unlike the chalcogenide–chalcogenide nanostructures, where the photo-induced effects may dominate. Low temperature solid-phase synthesis, phase separation can be performed this way. Stimulated structural changes in these multilayers may be used for efficient amplitude-phase modulated optical relief recording as well as for creating surface patterns with modified electrical parameters.     

Dipole oscillator strengths for Δn = 0 transitions in highly ionized sulfur

The foil-excitation method has been used to measure f-values for intra L-shell transitions in highly ionized sulfur.     

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.     

Ionic transitions and oscillator strengths in Debye plasma - a case study

Stability and energy of the excited states of the ion in plasmas are investigated theoretically using the Debye model. The transition energies of and transitions are seen to follow completely opposite trends of variation with the plasma screening strength. The dependence of absorption oscillator strength values on the screening strength is also discussed. Received: 22 October 1997 / Accepted: 9 January 1998