Energy levels and probabilities of radiative transitions in the Kr IX ion

The energy levels of the 3d ⁹4l (l = 1–3) and 3p ⁵3d ¹⁰4l (l = 0, 1) configurations in the Kr IX ion and the probabilities of radiative transitions to the ground state from these excited states have been calculated within the relativistic perturbation theory using a zero-approximation model potential. The results are shown to be stable within this approximation. The well-known problem of anomalously low accuracy of the calculations of some higher lying singlet levels is considered.     

XeI and XeII radiative lifetimes and transition probabilities

The lifetimes of ten levels of the xenon atom and two levels of the ion were measured. The probabilities for several transitions are calculated. The effective decay cross section is calculated for collisions for the 2p₈ level of the xenon atom.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 3, pp.24–29, March, 1971.The authors thank V. S. Mel'chenko for assistance in this study.     

Some lifetimes and transition probabilities in Cu(I)

Radiative lifetimes of 7 levels in the Cu(I) 3d⁹ 4s4p configuration have been measured using a delayed coincidence technique; copper vapor was excited in an argon buffer gas and cross sections for collisional destruction of copper levels by argon were also obtained. Transition probabilities of the lines originating from these levels have been determined using the measured lifetimes and branching ratios.     

Breit-Pauli energy levels and radiative lifetimes in neutral chlorine

Breit-Pauli Energy levels, oscillator strengths and transition probabilities for all the transitions in Cl I between the fine structure levels of 3s² 3p⁵, 3s² 3p⁴3d, 3s² 3p⁴4s and 3s²3p⁴4p states are calculated using extensive configuration interaction (CI) wave functions. We have also determined the lifetimes of 3s² 3p⁴3d, 3s² 3p⁴4s and 3s² 3p⁴4p levels. The relativistic effects are included through Breit-Pauli approximation via spin-orbit, Darwin and mass correction terms. Prior to the calculations of the oscillator strengths and transition probabilities, we fine-tune the CI coefficient using experimental energies. Our results are compared with experimental and other available theoretical data. The calculated energy levels are in close agreement with most of the NIST compiled data. We predict new lifetime data for several levels where no other theoretical and/or experimental results are available, which will form the basis for the future experimental work. Electronic supplementary material Online Material     

Transition probabilities and lifetimes of the low-lying levels of Fe XIV

The multi-configuration Dirac-Fock method is employed to calculate the transition energies,probabilities,and oscillator strengths for electric dipole allowed(E1) and forbidden(M1,E2,M2) lines for the 3s23p,3s3p2,3s23d,3p3,and 3s3p3d configurations of Fe XIV.The lifetimes of all 40 levels of these low-lying configurations are also derived.The valence-valence and core-valence correlation effects are accounted for in a systematic way.Breit interactions and quantum electrodynamics(QED) effects are estimated in subsequent relativistic configuration interaction(CI) calculations.The present results are in good agreement with other available theoretical and experimental values,and therefore can be used for the further astrophysical investigations.     

硅（Si）原子高激发态能级自然辐射寿命的测量

能级的自然辐射寿命是确定跃迁几率和振子强度所需的重要参数. 目前,硅原子高激发态能级自然辐射参数的实验数据还很缺乏,因此本文运用时间分辨激光诱导荧光和激光烧蚀等离子体技术,测量了硅原子位于47351.55 ~ 63844.65 cm?1之间的14个高激发态能级的自然辐射寿命. 实验结果分布在8.7 ~ 43.4 ns之间,测量误差均小于10%,其中9个能级的结果属于首次报道. 本文结果与可靠的分支比数据相结合可确定相关能级的跃迁几率和振子强度实验值.     

Theoretical calculation of energy levels and radiative lifetimes of Tl I

Considering the perturbation, the results of theoretical calculation of five Rydberg series energy levels 6s2ns^2S1/2 （n = 7 - 20）, 6s^2nd^2D3/2 （n = 6 - 20）, 6s^2nd^2D5/2 （n = 6 - 20）, 6s^2np^2P1/2^0 （n = 7- 20）, and 6s^2np^2P3/2^0 （n = 7-20） for Tl I are presented using the weakest bound electron potential model （WBEPM） theory. Furthermore, the radiative lifetimes of this five series are also calculated. The calculated values of energy levels and lifetimes are in good agreement with the experimental results.     

Experimental transition probabilities in N III,N IV and N V spectra

We have obtained transition probabilities (Einstein's A values) of thirteen transitions in doubly (N III), six in triply (N IV) and two in four times (N V) ionized nitrogen spectra belonging to the 3s-3p and 3p-3d transitions using a relative line intensity ratio (RLIR) technique. The linear low-pressure pulsed arc was used as an optically thin plasma source operated at 51 400 K electron temperature and 2.2×10²³ m^-3 electron density in nitrogen plasma. Our A values are compared to recent theoretical and experimental data. Received 18 December 2001 / Received in final form 29 January 2002 Published online 28 June 2002     

Experimental transition probabilities in the Ar III and Ar IV UV spectra

We present transition probabilities (Einstein's A values) for 38 Ar III (doubly ionized argon) and 14 Ar IV (triply ionized argon) spectral lines from the wavelength interval 240–308 nm. Considered spectral lines are recorded in laboratory pulsed discharge. The relative line intensity ratio procedure has been applied in evaluation of transition probabilities. As a reference for transition probability evaluation we have chosen A value of 241.884 nm spectral line in Ar III spectrum and A value of 280.947 nm in Ar IV spectrum, both obtained theoretically. Careful analysis of experimental and existing theoretical data is conducted in order to deduce uncertainties. Presented Ar III and Ar IV A values are for the first time obtained relying on experimental data.     

Reradiation effects,lifetimes and probabilities of band-to-band transitions in direct A3B5 compounds of GaAs type

A determination has been made of the efficiency and decay time of edge emission for some direct band-gap A₃B₅ semiconductor compounds (the active region of matched heterostructures) with the reradiation effect being taken into account. It has been established that the lifetime of minority carriers is due to band-to-band radiative transitions, the rate of which correspond to the simple quantum-mechanical theory.     

Calculation of collisional and radiative transition probabilities between excited argon levels

Average radiative transition probabilities for argon atoms have been calculated for transitions between 24 levels in two groups characterized by the atomic core terms ²P_1/2 and ²P_3/2 by using the method of Bates and Damgaard. The results are compared with data in the NBS tables (Wiese et al.) and with those of Katsonis and Drawin. We find satisfactory agreement for the order of magnitude, even for transitions between lower lying levels. Parameters, which appear in Drawin's semiempirical cross-section expressions for electronic excitation of optically allowed and parity-forbidden transitions, are determined with the multipole expansion method proposed by Sobel'man for transitions between the specified levels. Most of these are easily obtained, but the method must be improved for transitions between levels having the same azimuthal quantum number because the summation over the constituent terms does not converge.     

单电离态Kr原子的能级寿命的研究

在 12 0keV的能量下 ,用束 -箔方法研究了跃迁强谱线的单电离态Kr原子激发态能级5p4 D07/2 ,5p4 D05/2 的寿命。并与理论和其它实验结果做了比较和讨论。     

Fourier spectroscopy of radiative transitions between Landau levels in InSb

Radiative transitions between Landau levels were analyzed by Fourier spectroscopy in n-InSb. The experiments were carried out at cyclotron resonance frequencies below and above the optical phonons. Two types of transitions between Landau levels were observed, namely between free carrier states and between impurity states. Compared with absorption data the emitted lines are shifted to smaller energies. At energies above the LO phonon the emitted lines are affected by the electron-LO phonon coupling. An analysis of the line width revealed the important influence of self-absorption.     

Relativistic calculations on the transition electric dipole moments and radiative lifetimes of the spin-forbidden transitions in the antimony hydride molecule

Calculations on the spectroscopic constants and transition properties of the first three states (${\rm a}^{1}\Delta $, ${\rm b}^{1}\Sigma^{+}$, and X$^{3}\Sigma^-$) of the SbH molecule were performed under the relativistic framework using the exact two-component Hamiltonian (X2C). The potential energy curves in the Franck-Condon region were computed and compared with the previous values. Furthermore, the transition dipole moments for the weak spin-forbidden transitions (${\rm b}0^{+}$-X$_{1}0^{+}$, ${\rm b}0^{+}$-X$_{2}$1, X$_{1}0^{+}$-X$_{2}$1, and X$_{2}$1-${\rm a}$2) were reported. The spontaneous radiative lifetime of the ${\rm b}^{1}\Sigma^{+}$ ($\upsilon '=0$) state was calculated as 163.5 $\pm$ 7.5 μs, which is in reasonable agreement with the latest experimental value of 173 $\pm$ 3 μs. The spontaneous radiative lifetimes of the X$_{2}$1 ($\upsilon '=0$) state and the ${\rm a}$2 ($\upsilon '=0$) state were calculated to be 48.6 s and $\sim 8 $ ms, respectively. Our study is expected to be a benchmark transition property computation for comparison with other theoretical and experimental results. The datasets presented in this paper, including the transition dipole moments, are openly available at https://dx.doi.org/10.11922/sciencedb.j00113.00018.     

Radiative lifetimes and transition probabilities in Ta I

Radiative lifetimes of 14 odd-parity Ta I levels, belonging to the 5d³6s6p and 5d⁴6p configurations in the energy range from 30 664 to 45 256 cm^-1, have been measured using the time-resolved laser-induced fluorescence technique. Extensive calculations, taking configuration interactions and core-polarisation effects into account, are able to reproduce in a satisfying way the available experimental results but suffer from the rather fragmentary knowledge of the level structure of this atom. New transition probabilities are deduced for a set of strong lines depopulating the levels investigated experimentally in the present work.     

Theoretical study of nonadiabatic interactions,radiative lifetimes and predissociation lifetimes of excited states of BH

Ab initio multireference configuration interaction calculations have been carried out on the lower-lying electronic states of BH and their nonadiabatic interactions. The ab initio data have been included in subsequent calculations involving solution of the complex eigenvalue Schrödinger equation to determine predissociation widths and lifetimes of vibrational-rotational levels of these states. Secondly, previously calculated ab initio data on the Rydberg states and their nonadiabatic interactions have been included in multi-state vibrational calculations on the 3p and 3d complexes in BH and BD. The results are in good agreement with the experimental analysis of the 3p and 3d spectra in BH and BD. Furthermore, interaction of the 3d states with the neighbouring 4s state is also found to be important.     

The spin-orbit term in radiative transitions of hadrons

We point out that one finds in the literature two different results for the spin-orbit term in radiative transitions of hadrons. We analyze the problem and find that, besides the term usually quoted $$ - ie\omega (\sigma \times p) \cdot \varepsilon _\gamma /4m^2 \cong e[\nabla (V_v + V_s ) \times \sigma ] \cdot \varepsilon _\gamma /4m^2 $$ (V _v ,V _s are the Lorentz vector and scalar pieces of the binding potential and ω the photon energy), there is another term that gives as final resulte(?V _v ×σ)·ε ^γ/2m ². We use for our proof two different approaches: the Foldy-Wouthuysen transformation, and the method of Brodsky and Primack based on a dipole formula. In hadrons, the electric field has two pieces, the photon radiation field, and a strong interaction piece, of order 1/e relative to the former. These two pieces are at the origin of the two spin-orbit terms at the order (v/c)³.     

Transition probabilities, oscillator strengths and lifetimes for singly ionized magnesium

The electric dipole transition probabilities, oscillator strengths and lifetimes have been calculated using the weakest bound electron potential model theory (WBEPMT) for singly ionized magnesium. In the calculations both multiplet and fine structure transitions are studied. We have employed both the numerical Coulomb approximation (NCA) method and numerical non-relativistic Hartree-Fock (NRHF) wave functions for expectation values of radii. The calculated oscillator strengths and lifetimes have been compared with MCHF results given by Fischer et al. (2006). A good agreement has been obtained with the MCHF results. Moreover, some new transition probabilities, oscillator strengths and lifetime values, not existing in the data bases for highly excited levels in singly ionized magnesium, have been obtained using this method.     

Theoretical calculation of transition probabilities and lifetimes of levels of the 4d 95p configuration of CdIII

The configuration superposition method realized in the basis of Hartree-Fock functions and transformed radial orbitals with variable parameters is applied to ab initio calculation of electronic transition probabilities from levels of the 4d ⁹5p configuration of the CdIII ion. Relativistic corrections in the energy spectra are calculated within the framework of the Hartree-Fock-Pauli approximation, i.e., in the second order in the fine structure constant. The inclusion of correlation and relativistic corrections makes it possible to achieve a good coincidence of the values of electric dipole transition probabilities calculated with the use of two forms of the operator—the form of length and the form of velocity—for both strong and weak transitions. Using the transition probabilities obtained, radiative lifetimes of levels of the configuration indicated are determined. They are in a good agreement with the currently available experimental data.