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.     

Effective charges for radiative and Auger transition probabilities

Analyses of higher-order resonant, atomic collision processes require many accurate radiative and Auger transition probabilities, A_r and A_a. Numerical evaluation of these probabilities for high Rydberg states and for large angular momenta is difficult. We develop here Coulombic expressions for A_r and A_a, with effective charges for the individual orbitals involved. Simple formulas for the effective charge are proposed and tested against the more accurate data obtained with Hartree—Fock wave functions.     

Auger and radiative transition probabilities of high Rydberg states

The dependence of the Auger and radiative transition probabilities of high Hydberg states on their principal and orbital quantum numbers n and l is studied. Based on explicit calculations, a simple empirical l-dependence of the gaussian type is obtained, which differs drastically from any of the previously assumed behavior.     

Measured collisional radiative coefficients of the 4p groups of the argon I and argon II systems

We determine the r¹ (p) coefficients of the argon I 4p ¹P₁ state (2p₂ with Paschen notation) with the λ = 696.5 nm line and of the argon II 4p ²D_{$\text{5}\text{2}$} state with the λ = 488.0 nm line in a highly ionized, low temperature (T_{e = 3?4 eV}), magnetically confined (0.2 T) plasma of a hollow cathode arc with electron densities n_e between 10¹⁹ and 10²⁰ m^?3. The neutral density n₀ is 10¹⁹ m^?3 or less. The r¹ (4p) values are (6 ± 2) × 10^?5 for argon I and (5 ± 2) × 10^?4 for argon II.     

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.     

Atomic radiative transition probabilities in a continuous medium

A simple quantization procedure is applied to the electromagnetic radiation field in a nondissipative, weakly dispersive continuous medium. The resulting operator expressions for the electric and magnetic field strengths are used to study the influence of the dielectric and magnetic properties of the medium on the Einstein coefficients for spontaneous and stimulated radiative transitions of single atoms or molecules embedded in the medium. The expressions obtained are consistent with detailed-balance considerations.     

Calculation of radiative heat transfer in argon arc plasmas

Radiation emission and absorption in arc plasmas are important energy transfer processes. Exact calculations, though possible in principle, are usually impossible in practice because of the need to treat a large number of spectral lines and also the continuum radiation in the whole spectrum range. Recently, we have used an approximate method of partial characteristics to evaluate the radiation intensities, radiation fluxes and the divergence of radiation fluxes for SF₆ arc plasma with cylindrical symmetry. In this paper, we have extended our calculations toargon arc plasmas for the plasma pressures of 0.1, 0.5 and 1.0 MPa. We have calculated the coefficients of absorption for Ar plasmas at temperatures from 300 to 35 000 K, and have used these coefficients to calculate the partial characteristics. Both the continuum and the line spectra have been included in calculations. We have taken into account the radiative photo-recombination and bremsstrahlung for the continuous spectrum, and over 500 spectral lines for the discrete spectra.The method of partial characteristics has been applied to three-dimensional calculations of radiative heat transfer — i.e. radiation intensity, radiation flux and its divergence — in simplified temperature profiles. Conclusions have been made concerning validity and utilization of the method of partial characteristics in general gas dynamics problems.     

Configuration temperatures in a hollow cathode argon arc and transition probabilities of the argon II spectrum

A comparison has been made between some kinds of configuration temperatures of the argon II spectrum and the temperatures of the atoms, ions and electrons for a hollow cathode, low-pressure, magnetically-confined, argon arc discharge in the 10–80 A current region. We found that thermalization by heavy particle collisions does not occur within the 4p group of the argon II spectrum (excitation energies 19·22-19·97 eV). and that relative line-intensity measurements over a large spectral range of 19–25 eV give hardly any relevant information on the electron temperature. Our conclusion is that the population densities of the excited levels are mainly determined by the excitation cross-section functions for the levels concerned. Furthermore, we have compared published transition probabilities (to 1970) for the argon II 4p group transitions. The mean values were obtained for 31 transitions with uncertainties (with two exceptions) between 1 and 20 per cent.     

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.     

Multireference CI calculations of radiative transition probabilities between low lying quartet states of the C2+ ion

Potential energy functions for the ten lowest electronic states of the C₂⁺ ion have been calculated from correlated CASSCF and MC-CI electronic wavefunctions and used for derivation of the spectroscopic constants. The predicted values are expected to be accurate within 0.01 Å for R_e, 20–30 cm⁻¹ for ω_e and 0.05–0.1 eV for T_e. For the three lowest quartet states the electronic transition moment functions have also been calculated. For the transitions among these states, radiative lifetimes and absorption oscillator strengths are given which should be accurate within about 15%.     

Two-dimensional images of radiative and metastable excited stateradial profiles for an inductively coupled plasma in argon

Inductively coupled plasma (ICP) was shown to be characterized by a substantial degree of stepwise excitation due to a large density of metastable atoms and an even larger population of electrons. The kinetics of metastables strongly affects the structure of the discharge and we have applied laser absorption spectroscopy to establish the density profile of argon metastables Ar(1s₅) in a single turn coil geometry. At the same time the radial profiles of the radiative Ar(3p₅) state obtained by using a computer-aided tomography are significantly different indicating the effect of electron induced quenching and stepwise processes in kinetics of the two states     

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.     

Measurement of the collisional transition rate between the hydrogen levels n = 3 and n = 4

The ratio of the collisional transition rate C₄₃ and the total loss rate V₄ of the level n = 4 has been measured by means of dye-laser fluorescence in a rf hydrogen plasma. In a further experiment using a nitrogen-laser-pumped dye-laser (with pulses short compared to the life time of the n = 4 level), the total loss rate V₄ of this level has been determined by observing the exponential intensity decay of the H_β line. From the results of these two experiments, the excitation rate C₄₃ is obtained. Agreement with theoretical values is found.     

Experimental and theoretical radiative properties of odd-parity highly excited levels in Mo II

Investigations are made for the collective spontaneous emission of a Bose-Einstein condensate consisting of N two-level atoms when s atoms are initially excited in a multi-photon q-deformed Dicke model. The model is based on the generalized deformed oscillator algebra in which the field radiation operators are deformed by an operator-valued function $f\left( {\hat n} \right)$ of the photon number operator $\hat n$ . The time evolution of the expectation value of the atomic inversion is calculated for s = 1, s = 2 and s = 3. When s = 3 its spectra are characterized by nonequidistant eigenvalues, and the phenomenon of the quantum collapse and revival is demonstrated. In particular, the influences of photon multiplicity and q-deformation on the spontaneous emission of the system are discussed. The results show that the nonlinearities due to the photon multiplicity and q-deformation may lead to the inhibition of collective spontaneous emission.     

Energy levels and transition probabilities in 130Sn

The excited states of ¹³⁰Sn have been studied in the decay of three different isomers of ¹³⁰In. The experimentally determined energy levels and transition probabilities are compared with comprehensive shell-model calculations using the full neutron single-hole configuration space. Additional theoretical and experimental data regarding ¹²⁸Sn are also presented.     

The theoretical calculation of transition probabilities for some excited p-d transitions in atomic nitrogen

The atomic transition probabilities are calculated for individual lines between some quartet terms of 3p↦4d and 3p↦5d transition arrays using weakest bound electron potential model theory (WBEPMT). In the determination of relevant parameters which are needed for calculation of transition probabilities, we employed numerical non-relativistic Hartree-Fock wave functions for expectation values of radius in both ground and excited states unlike to NCA method used on traditional WBEPMT procedure. We have obtained very good agreement between our results and the accepted values taken from NIST.     

Difference between radiative transition rates in atoms and antiatoms

We demonstrate that CP violation results in a difference of the partial decay rates of atoms and antiatoms. The magnitude of this difference is estimated.     

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。     

Non-LTE population probabilities of the excited ionic levels in a steady state plasma

A Complete-Steady-State (CSS) model for the charge state distribution and the ionic levels population probabilities of ions in hot non-LTE plasmas is described. The following properties of this model are described in the paper: (i) it is shown that CSS covers LTE and Corona Equilibrium (CE) in the high and low electron density regimes respectively, (ii) an explicit expression is founf for the low electron density asymptotic behavior of the population probabilities, (iii) it is shown that at intermediate density regions the CSS model predicts results similar to that of the Quasi-Steady-State model, (iv) new validity limits are derived for LTE and CE, (v) the population distribution of the excited levels is revised, (vi) an analytical expression is found for the high electron density asymptotic behavior of the population distribution, (vii) the influence of the radiation reabsorption in a spherically symmetric CSS plasma is briefly described, and (viii) the effect of the inaccuracies in the rate-coefficients on the results of CSS calculations is evaluated.     

Experimentally derived Auger transition probabilities in X-ray excited Auger electron spectroscopy (XAES)

The capability of Auger transition probabilities experimentally derived from X-ray excited Auger electron spectra in XPS were tested. The relative sensitivity factor (RSF) method has been employed in the quantification by AES (Electron excited Auger electron spectroscopy). However, the difference between experimentally derived RSF and theoretically calculated ones has been found in some reports. One of the great reason of the difference may be caused by the calculated values of the Auger transition yield which has been commonly employed without the consideration of the allotment of coupling scheme in the transition selected in the quantification, for instance, the allotment of each six coupling KL₁L₁, KL₁L₂, KL₁L₃, KL₂L₂, KL₂L₃, and KL₃L₃ in KLL transition. The employment of derived Auger transition probabilities reduce the difference between theoretically calculated RSF and experimentally derived one.