Oscillator strengths for 2 transitions of the lithium isoelectronic sequence

The nonrelativistic dipole-length, -velocity and -acceleration absorption oscillator strengths for the 1s²2s-1s²np (3 ￡ n ￡ 9)(3\leq n\leq 9) transitions of the lithium isoelectronic sequence up to Z=10 are calculated by using the energies and the multiconfiguration interaction wave functions obtained from a full core plus correlation (FCPC) method. In most cases, the agreement between the f-values from the length and velocity formulae is up to forth or fifth digit. Combining these discrete oscillator strengths with the single channel quantum defect theory (QDT), the discrete oscillator strengths for the transitions from the 1s^22s state to highly excited levels (n 3 10n \geq 10) and the oscillator strength densities corresponding to the bound-free transitions are obtained.     

Systematic trends of hartree-fock oscillator strengths along the sodium isoelectronic sequence

Hartree-Fock wavefunctions for 1s²2s²2p⁶nl (nl = 3,4,5s; 3,4,5p; 3,4,5d and 6f) configurations of the sodium isoelectronic sequence have been calculated up to Z = 26. Oscillator strengths for electric dipole transitions have been computed with the dipole length form of the transition matrix element. The study of systematic trends of these oscillator strengths along the isoelectronic sequence has allowed us to obtain new f-values and to improve some previous results.     

Hartree-Fock energies of D and D doubly excited states of the lithium isoelectronic sequence

Hartree-Fock energies of 1s2snd ⁴D, 1s2pnp ⁴D and 1s2pnd ⁴D⁰, n=3–5 of lithium isoelectronic sequence from Li to Ne⁺⁷ are reported. These results in conjunction with the energy of the lowest ⁴P and ⁴P⁰ states of the lithium isoelectronic sequence as calculated by Holoien and Geltman, are used to check some proposed assignments of lines obtained in beamfoil spectroscopy of Be(II), C(IV) and N(V).     

类钠等电子系列振子强度与原子实极化系数计算

应用屏蔽氢模型计算类钠等电子系列电偶极子跃迁振子强度f和原子(离子)实极化系数α,计算结果和有关文献是一致的;并讨论极化系数随主量子数、原子序数的变化情况.     

Discrepancies between theoretical and experimental atomic oscillator strengths of the sodium isoelectronic sequence resonance transition

Discrepancies between theoretical and experimental estimates of the oscillator strengths of the sodium isoelectronic sequence resonance transition are considered in the light of recent multi-configuration Hartree-Fock results. Possible experimental difficulties in the cascading analysis arising from a peculiar pattern of excited-state lifetimes are examined using computer simulations of decay curves.     

Oscillator strengths in the boron isoelectronic sequence

The quantum defect orbital formalism in both its relativistic and non-relativistic versions has been applied to the calculation of oscillator strengths in the sharp spectral series of some boron-like systems. The results are presented in both tabular and graphical forms.     

Systematic trends in the line strengths of E1 transitions in the oxygen isoelectronic sequence

Line strengthsS for the dipole allowed transitions within then=2 complex of the oxygen isoelectronic sequence have been fitted in the formZ ² S=A+B/(Z −C), whereZ is the nuclear charge of a particular ion. The constantsA, B andC are determined by using a non-linear least square method. The data forS are taken from the configuration interaction calculations which included internal, semi-internal and all external type correlations for ions in the rangeZ=8 − 25. It is shown that the values ofA obtained from the fit for all the transitions are in excellent accord with the ab-initio values obtained in the hydrogenic limitZ → ∞ provided near degeneracy effects are included in the ground state multiplet 1s²2s²2p^{4 1}S.     

A time-dependent Hartree-Fock study of the neon isoelectronic sequence

For a wide range of frequencies the time-dependent Hartree-Fock equations are solved numerically for atoms of the Ne isoelectronic sequence. From the solutions properties of each system are calculated, notably excitation energies and bound-bound oscillator strengths. Excellent agreement is observed between the TDHF oscillator strengths and the most accurate experimental and theoretical data which are currently available.     

Hartree-fock wave functions and oscillator strengths for the helium isoelectronic sequence

Oscillator strengths for 1¹S?n¹P transitions for some members of the helium isoelectronic sequence have been calculated by utilizing the dipole length, velocity and acceleration forms of the transition matrix element with coupled H.F. wave functions. Good agreement has been obtained between the values of the oscillator strengths. The quantities $\text{(?}{}_{\mathrm{A}}\text{??}{}_{\mathrm{L}}\text{)}$ and $\text{(?}{}_{\mathrm{A}}\text{??}{}_{\mathrm{V}}\text{)}$ decrease slowly with nuclear charge Z, whereas $\text{(?}{}_{\mathrm{L}}\text{-?}{}_{\mathrm{V}}\text{)}$ first increase to a maximum value and then decreases slowly.     

Relativistic Hartree-Fock oscillator strengths for the lowest s→p transitions in the first few members of the Rb(I) and Cs(I) isoelectronic sequences,with allowance for core polarization

Relativistic single-configuration Hartree-Fock oscillator strengths for the lowest ns²S_{$\text{1}\text{2}$}→ np²P_{$\text{1}\text{2}$,$\text{3}\text{2}$} transitions in the first few members of the rubidium (n = 5) and cesium (n = 6) isoelectronic sequences have been studied, both with and without allowance for core polarization. The effect of polarization of the core of the atom or ion by the valence electron is included by introducing a polarization potential in the one-electron Hamiltonian and by employing the corresponding correction for the dipole-moment operator in the transition matrix element. The results obtained compare well with available experimental data and indicate a significant influence of core-polarization effects on oscillator strengths. The behaviour of the oscillator strengths for the low Z part of the isoelectronic sequences is discussed.     

Relativistic and nonrelativistic oscillator strengths in the Na isoelectronic sequence

We report the general trend of the nonrelativistic Hartree-Fock relativistic Hartree-Fock, nonrelativistic configuration-interaction, and relativistic configuration-interaction length form of the oscillator strengths for the resonance excitation 1s ²2s ²2p⁶3s ² S _J ^e 1s ²2s ²2p ⁵3s ^{2 2} P _J ^o . transition, which leads to autoionization (Auger transition), in Na, Mg¹⁺, Al²⁺, Si³⁺, P⁴⁺, S⁵⁺, Cl⁶⁺, Ar⁷⁺, K⁸⁺, Ca⁹⁺, Sc¹⁰⁺, Ti¹¹⁺, Fe¹⁵⁺, Cu¹⁸⁺, Zn¹⁹⁺, Br²⁴⁺, and Kr²⁵⁺ ions of the sodium isoelectronic sequence.     

The forbidden transitions for magnesium isoelectronic sequences

Using the full relativistic quantum mechanics(GRASP2),we have calculated systematically the 3p2-3p1 and 3p1 -3p0 magnetic dipold m1 energy level scparations,transition probabilities and cscillator strengths in the 3s3p configuration of the magnesium seque     

Systematic trends in the line strengths and radial matrix elements of E1 transitions in the Be isoelectronic sequence

Line strengthS and radial matrix elementσ for the dipole allowed transitions withinn=2 complex of ions in the Be isoelectronic sequence have been fitted in the formsZ ² S=A+B/(Z − C) andZσ=A′ + B′/(Z − C′). The constantsA, B, C andA′, B′, C′ have been calculated by employing a non-linear least square method. The relevant data forS andσ have been taken from calculations which includes correlation effects. It is shown that the fitted yalues ofA andA′ are in excellent accord with their hydrogenic values (Z →α) provided that we express the zeroth-order wavefunction of the ground state 1s²2s^{2 1} S as a quantum-mechanical admixture of the Hartree-Fock (HF) state 1s²2s^{2 1} S and the near-degenerate state 1s²2p^{2 1} S.     

The polarised frozen-core approximation: Oscillator strengths for the boron isoelectronic sequence

Orbital wave functions of a large number of ns-, np-, and nd-levels of the first five members of the boron isoelectronic sequence have been calculated using a frozen-core Hartree-Fock procedure augmented by an l-dependent core polarisation potential. The calculated ionisation energies are generally in very good agreement with observations. Electric dipole oscillator strenghts have been derived from the calculated orbitals and energies and have been used to yield simple interpolation formulae for f-values of higher members of the sequence. They are expected to be of high accuracy in many cases.     

Energy and fine structure of the lithium isoelectronic sequence

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Relativistic Hartree-Fock oscillator strengths for the lowest s→p and p→d transitions in the first few members of the Ag(I) and Au(I) isoelectronic sequences,with allowance for cope polarization

Relativistic, single-configuration Hartree-Fock oscillator strengths for the lowest ns²S_{$\text{1}\text{2}$}→np²P_{$\text{1}\text{2}$$\text{3}\text{2}$} and np²P_{$\text{1}\text{2}$$\text{3}\text{2}$}→nd²D_{$\text{3}\text{2}$$\text{5}\text{2}$} transitions in the first few members of the silver (n = 5) and gold (n = 6) isoelectronic sequences have been studied, both with and without allowance for core polarization. Core polarization is included by introducing a polarization potential in the one-electron Hamiltonian and by employing the corresponding correction for the dipole-moment operator in the transition matrix element. The results obtained are compared with available experimental data and the influence of core-polarization effects on oscillator strengths is discussed.     

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.     

Oscillator strengths and lifetimes of levels for ions of the rubidium isoelectronic sequence calculated by the Dirac-Fock method

The oscillator strengths f of the resonance transitions are calculated by the Dirac-Fock method for the first ten terms of the rubidium isoelectronic sequence. The variation of f values along the isoelectronic sequence is analyzed. The corresponding transition probabilities and lifetimes τ of the levels 5p ² P _1/2 and 5p ² P _3/2 are calculated. The dependence of τ on the ion charge is approximated by an analytical equation. The obtained values of f and τ are compared with experiment and other calculations.     

类锂体系(Z=11～20) 1s~24s -1s~2np(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) 1s~24s -1s~2np(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1s~24s -1s~2np(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.     

Oscillator strengths and lifetimes calculated by the Dirac-Fock method for the levels of ions of the cesium isoelectronic sequence

A new method of data transmission in DWDM systems along existing long-distance fiber-optic communication lines is proposed. The existing method, e.g., uses 32 wavelengths in the NRZ code with an average power of 16 conventional units (16 units and 16 zeros on the average) and transmission of 32 bits/cycle. In the new method, one of 124 wavelengths with a duration of one cycle each (at any time instant, no more than 16 obligatory different wavelengths) and capacity of 4 bits with an average power of 15 conventional units and rate of 64 bits/cycle is transmitted at every instant of a 1/16 cycle. The cross modulation and double Rayleigh scattering are significantly decreased owing to uniform distribution of power over time at different wavelengths. The time redundancy (forward error correction (FEC)) is about 7% and allows one to achieve a coding enhancement of about 6 dB by detecting and removing deletions and errors simultaneously.