Transition probabilities for Ne I lines

Calculated transition probabilities for about 140 lines of Ne I are presented. The general agreement we have found with other existing data, for those values for which comparisons were carried out, verifies the reliability of our calculations and gives us confidence in these values for applications in astrophysics and plasma physics.     

Relativistic computation of intercombinational transition probabilities

Expressions have been obtained on the basis of S-matrix theory for the computation of electrical multipole transition probabilities in a relativistic approximation in a multielectron atom in first-order field perturbation theory. Also considered are corrections corresponding to simultaneously taking account of the external field and the interelectron interactions. Results of computing the wavelengths and probabilities of intercombinational transitions in multicharge ions between the configurations 1s 2p-1s² for 4 ≤ Z ≤28 and 1s² \(2s^n 1 2p^{n_2 } - 1s^2 2s^{n_1 \pm 1} 2 p^{n_2 \pm 1} \) for20 ≤ Z ≤ 30 are presented. The data obtained can be used to interpret soft x radiation originating in transitions observed in the solar corona and high-temperature plasma laboratories.     

Transition probabilities of OI spectral lines

Dipole transition probabilities connecting the 1s²2s²2p³(⁴S⁰)nl^3,5L_J levels are presented for (nl) up to (15,5). The calculations are based on the single-configuration Hartree-Fock wave functions with the 1s and 2s orbitals treated as a frozen core. The results generally agree well with earlier works (theoretical and experimental) on transitions involving low quantum numbers.     

Relative transition probabilities of F(I) spectral lines in the visible

The relative transition probabilities of 36 neutral fluorine lines were determined by photoelectric measurements of the spectral lines emitted from a wall-stabilized arc operated in argon-fluorine mixtures. The arc current was varied from 50–70 A, the electron concentration from 1.25 to 1.55 x 10²³m^-3, and the temperature from 13,600 to 14,300 K. The assumption of LTE was used for optically thin spectral lines. The electron concentration was measured by introducing a small quantity of hydrogen, and the temperature was determined from the relative intensities of Ar lines. Close agreement was found with other experimental data obtained from arc sources.     

Transition wavelengths and probabilities for spectral lines of Zr III

Wavelengths and oscillator strengths for all 4d4f↦4d² dipole-allowed fine-structure transitions in Zr III have been calculated within the Multi-Configuration Dirac-Fock method with QED corrections. These transitions are included in the spectrum of some chemically peculiar stars, like the B-type star χ Lupi observed by the Hubble space telescope. The results are compared to existing experimental and semi-empirical data.     

Energy levels and spectral lines of Ne VII

All experimental data on Ne VII, including previously unpublished beam-foil spectroscopy data, have been compiled and critically evaluated. More than a hundred spectral lines have been newly identified. For 40 transitions, the previous identifications have been revised. These revisions resolved all existing contradictions between previously published interpretations of the spectrum. An optimized level scheme has been derived from the total list of observed lines. About a hundred new energy levels have been found, including several highly excited hydrogenic levels. Based on these newly determined levels, as well as on the analysis of theoretical data, the ionization potential has been newly determined with improved confidence. Electronic supplementary material Online Material     

Energy levels and spectral lines of Ne VIII

All experimental data on the valence-shell-excited and core-excited spectra of Li-like neon, including previously unpublished beam-foil spectroscopy data, have been compiled and critically evaluated. Seventeen spectral lines have been newly identified. Sets of recommended energy levels have been derived from the total list of observed lines and from selected results of theoretical and semi-empirical calculations. An accurate value of the ionization potential has been derived from existing theoretical calculations. Electronic supplementary material Online Material     

Transition probabilities of some lines of Ne(I)

Relative transition probabilities for twenty-four spectral lines belonging to 3p-3d transition array of neutral neon have been determined by means of emission line-intensity measurements. The lifetime of the 3d(3/2)₂ level has been measured by the delayed coincidence method obtaining a value of 20.5±2.0 ns. With this lifetime value and taking into account the 3887.1 Å forbidden line, the transition probabilities of the lines with origin in the 3d(3/2)₂ level were put on an absolute scale. The experimental values of the present work are compared with theoretical calculations obtained by use of the Coulomb approximation and intermediate coupling scheme.     

Relativistic calculations of one-photon transition probabilities in hydrogen-like ions

The one-photon transition probabilities in hydrogen-like ions are calculated for nuclear charge numbers in the range 1 ≤ Z ≤ 100. The calculations are performed in the framework of the relativistic Dirac’s theory for the states with the principal quantum numbers n = 2,3, 4. The finite nuclear size effect is taken into account. The role of the quantum electrodynamics (QED) and nuclear recoil corrections is also considered.     

Level mixing induced transparency II. Different transition probabilities of the crossing lines

In one of our previous papers (R.N. Shakhmuratov et al. Appl. Phys. B. 81, 883 (2005)) we presented a new type of spatiotemporal interference of gamma radiation propagating in a resonant medium. The excitation scheme consists of two identical V-schemes, each being formed by one type of the transition: one is induced only by the left circular polarized field and the other by the right circular polarized field. The coupling of these V-schemes through level crossing allows resonant scattering of a photon in the forward direction with a change of its polarization. As a result the radiation field, which is resonant with a transition from the ground state to one of the two sublevels of the excited state, develops in a particular combination of radiation fields with left and right circular polarizations, called a normal mode. This combination is much less absorbed in subsequent layers of the absorber. For identical V-schemes, the structure of the modes is fairly simple. In this paper, we show that a similar reduction of absorption is realized for non-identical V-schemes, differing in transition strengths. The structure of the normal modes is found and they have a more complicated form. This general case is actually realized in a level crossing experiment in gamma optics. PACS 42.50.Gy; 33.45.+x     

Stark widths and shifts of several prominent Ne I spectral lines

Stark widths and shifts of six prominent Ne I spectral lines have been measured in linear pinch plasma sources and compared with existing theoretical and experimental results.     

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.     

The calculation of transition probabilities between individual lines for atomic lithium

The atomic transition probabilities for individual and multiplet lines of lithium atom are obtained using weakest bound electron potential model theory (WBEPMT) and exact quantum defect theory. The results obtained using two different methods agree very well with the accepted values taken from NIST, MCHF results and Opacity Project values. These methods require substantially less computational time than well-known theoretical methods, thereby permitting the study of 108 transitions.     

Comments on transition probabilities of Argon II

A comment is given on the method of determining transition-probability values in a previous paper of one of the authors. A revised table of values of some Argon II transitions is presented.     

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

Calculations are reported of relativistic ionization energies and transition probabilities in the one-electron spectrum of singly-ionized ytterbium. The relativistic model potential approach used takes into account both valence-core electron exchange and correlation. The influence of polarization of the core by valence electrons on ionization energies and transition probabilities has been studied. Strong cancellation effects have been found for higher transitions of the principal series; these affect both transition probabilities and relative line strengths. The energies are predicted for some states which have not yet been experimentally localized. The static dipole polarizability for Yb⁺ is estimated to be 48.18 g₀³ from computed oscillator strengths; this estimate is compared with lower bounds determined from experimental data.     

Lifetimes and transition probabilities of Ar(II)

Radiative lifetimes of 16 levels belonging to the 3p⁴4p configuration of Ar(II) have been measured by using the delayed-coincidence method. Relative transition probabilities for 87 lines arising from these levels have been determined from emission line-intensity measurements. By using the corresponding experimental lifetimes, the relative transition probabilities were put on an absolute scale. Our experimental results are compared with experimental and theoretical data given by other authors and with our calculations in LS coupling.