scholarly journals X-Ray Satellite Lines

1984 ◽  
Vol 86 ◽  
pp. 36-36
Author(s):  
J. Dubau
Keyword(s):  
Transition Probabilities ◽  
Relativistic Effects ◽  
Radiative Transition ◽  
Electron System ◽  
Great Accuracy ◽  
Atomic Data ◽  
X Ray ◽  
Spectroscopic Diagnostics ◽  
Radiative Transitions ◽  
Shell Vacancy

Satellite lines are typical features of X-ray spectra. They correspond to radiative transitions involving an inner-shell vacancy. The most studied satellite lines are of the - type, i.e., (ls–2p) transition.With the advent of Space Astronomy, X-ray spectra emitted by very hot solar plasma have been obtained. By a simple comparison of different spectra, it appears that, for highly ionized atoms, some satellite lines have intensities as large as resonance lines intensities and, more particularly, this is the case for the ls2n. – ls 2pn satellite lines of the 1s2 – ls2p resonance lines.The analysis of the different population mechanisms responsible for the satellite lines and resonance lines emission has shown that different spectroscopic diagnostics could be derived from line ratios only if atomic data of great accuracy were available. There exists nowadays different atomic data programs adapted to X-ray satellite lines. They have in common to give a great amount of data simultaneously: wavelengths, autoionization and radiative transition probabilities. They take into account correlation and relativistic effects.After tackling the simple 3-electron system, the programs give now appropriate data for more complex systems but this required large computers because the lines become blended. It is therefore impossible to limit the calculation to the most intense lines.

scholarly journals Radiative transitions for three lowest configurations of tungsten ions W38+–W43+

2017 ◽  
Vol 57 (3) ◽  
Author(s):  
Rasa Karpuškienė ◽  
Pavel Bogdanovich ◽  
Romualdas Kisielius
Keyword(s):  
Transition Probabilities ◽  
Relativistic Effects ◽  
Electric Quadrupole ◽  
Radiative Transition ◽  
Configuration Interaction Method ◽  
Hartree Fock ◽  
Radiative Transitions ◽  
Emission Transition ◽  
Magnetic Quadrupole ◽  
Electron Correlation Effects

The ab initio quasirelativistic approximation was used to derive transition data for the multicharged tungsten ions W38+–W43+ with an open 4p shell. The configuration interaction method with transformed radial orbitals was applied to include electron correlation effects. The relativistic effects were taken into account in the Breit–Pauli approximation for the quasirelativistic Hartree–Fock radial orbitals. The level energies E, radiative lifetimes τ, and Landé g-factors were calculated for the 4s24pN, 4s24pN–14d, and 4s4pN+1 configurations of six tungsten ions. The radiative transition wavelengths λ, spontaneous emission transition probabilities A and their uncertainties for the electric dipole, electric quadrupole, electric octupole, magnetic dipole and magnetic quadrupole transitions among the levels of these configurations are presented.

An Investigation on the Fine Structure Levels in the Ground State Configuration for the Antimony Anion

2014 ◽  
Vol 69 (8-9) ◽  
pp. 397-402
Author(s):  
Leyla Özdemir ◽  
Sadiye Tuna
Keyword(s):  
Fine Structure ◽  
Ground State ◽  
Transition Probabilities ◽  
Relativistic Effects ◽  
Electric Quadrupole ◽  
Radiative Transition ◽  
Ground State Configuration ◽  
Hartree Fock ◽  
First Time ◽  
State Configuration

We have investigated the correlation, relativistic, and isotope shift effects on the fine structure levels in the ground state configuration for the antimony anion ( Sb-). Energies and radiative transition probabilities (for magnetic dipole, M1, and electric quadrupole, E2) have been obtained using the multiconfiguration Hartree-Fock method within the framework of the Breit-Pauli Hamiltonian. Therefore, the most important configuration interaction and relativistic effects have been included. Comparisons with other available works are presented. For some M1 and E2 lines the considered transition probabilities are reported for the first time

scholarly journals Chromospheric and Coronal Spectra

1995 ◽  
Vol 10 ◽  
pp. 580-582
Author(s):  
Carole Jordan
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Relativistic Effects ◽  
Uv Spectra ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Recombination Rates ◽  
Electron Collisions ◽  
Close Coupling ◽  
Radiative Processes

The interpretation of chromospheric and coronal spectra requires accurate ionization and recombination rates, collision strengths and transition probabilities. Recent projects to improve calculations of opacities in stellar interiors have led to a large amount of new atomic data. Some current and potential applications of atomic data to chromospheric and coronal spectra are mentioned below.Strong chromospheric lines are optically thick, and the solution of the radiative transfer equations can depend on atomic data for other species contributing to the background opacity. Many lines in the spectra of stars with hot coronae are excited by electron collisions, but in the cooler non-coronal giants radiative processes involving the H Lyman α and β lines become more important (see Jordan 1988a). Photo-ionization rates from ground configuration excited terms and oscillator strengths to high levels are still needed.Fe II is an important ion producing emission lines in stellar chromospheres. Several excitation mechanisms contribute to the observed spectra (Jordan 1988b). Permitted lines to the ground term and low lying metastable terms have high optical depths and transfer photons to spin forbidden lines sharing a common upper level (e.g. mults. uv 1 and uv 3 transfer photons to mults. uv 32 and 61). Line intensity ratios yield the optical depth in the optically thick lines. The strong H Ly α line in cool giants and supergiants excites high levels in Fe II, resulting in strong decays in multiplets such as uv 391 and 399. A large number of f-values are required to interpret the lines formed by these radiative processes. Nahar & Pradhan (1994) have published some results from the Opacity Project, calculated by using the close coupling method and observed energy levels (which introduce some allowance for relativistic effects). In most cases these f-values agree with experimental results and the calculations by Kurucz (1988) to within 10%. The latter are still needed for the interpretation of stellar uv spectra because of the treatment of spin-forbidden lines.

scholarly journals Atomic Databases: Four of a Kind

Atoms ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 30 ◽  
Author(s):  
Claudio Mendoza
Keyword(s):  
Data Dissemination ◽  
Transition Probabilities ◽  
Radiative Transition ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Atomic Data ◽  
Distributed Data ◽  
Design Strategies ◽  
Scientific Database ◽  
Assessment Environment

In the context of atomic data computations for astrophysical applications, we review four different types of databases we have implemented for data dissemination: a database for nebular modeling; TIPTOPbase; OPserver; and AtomPy. The database for nebular plasmas is briefly discussed as a study case of a successful project. TOPbase and the OPserver were developed during the Opacity Project, an international consortium concerned with the revision of astrophysical opacities, while TIPbase was part of the Iron Project to calculate radiative transition probabilities and electron impact excitation collision strengths for iron-group ions. AtomPy is a prototype for an open, distributed data-assessment environment to engage both producers and users. We discuss design strategies and implementation issues that may help in the undertaking of present and future scientific database projects.

scholarly journals Benchmarking Current Capabilities for the Generation of Excitation and Photoionisation Atomic Data

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 90 ◽  
Author(s):  
Catherine Ramsbottom ◽  
Connor Ballance ◽  
Ryan Smyth ◽  
Andrew Conroy ◽  
Luis Fernández-Menchero ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Cross Sections ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Radiative Transition ◽  
Atomic Data ◽  
High Quality ◽  
Astronomical Instruments ◽  
First Time ◽  
Line Strengths

The spectra currently emerging from modern ground- and space-based astronomical instruments are of exceptionally high quality and resolution. To meaningfully analyse these spectra, researchers utilise complex modelling codes to replicate the observations. The main inputs to these codes are atomic data such as excitation and photoionisation cross sections, as well as radiative transition probabilities, energy levels, and line strengths. In this publication, the current capabilities of the numerical methods and computer packages used in the generation of these data are discussed. Particular emphasis is given to Fe-peak species and the heavy systems of tungsten and molybdenum. Some of the results presented to highlight certain issues and/or advances have already been published in the literature, while other sections present new recently evaluated atomic data for the first time.

Kα transition probabilities of C-like to F-like Al ions

2015 ◽  
Vol 93 (3) ◽  
pp. 267-270
Author(s):  
Cuicui Sang ◽  
Feng Chen ◽  
Chao Chen ◽  
Bingcong Gou
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Emission Spectra ◽  
Radiative Transition ◽  
Transition Rates ◽  
Atomic Structures ◽  
Radiative Transitions ◽  
Electron Correlation Effects ◽  
Reasonable Description ◽  
Spectral Intensities

Kα radiative transitions of C-like to F-like Al ions are studied using the multiconfiguration Dirac–Fock (MCDF) method. The fully relativistic MCDF approach was specifically designed to calculate atomic structures and radiative transition rates, and hence it ensures a reasonable description of the emission effects and spectral intensities. The energies and wavefunctions, corresponding mixing coefficients, the influence of electron correlation effects on energy levels, and radiative transition rates for C-like to F-like Al ions are investigated in detail. Good agreement is found between the calculated Kα emission spectra in this work and the spectra from experimental measurements.

Satellite dielectronic spectra created from autoionizing 2lnl' and 1s2lnl' states with n = 4–5

2000 ◽  
Vol 78 (12) ◽  
pp. 1055-1067 ◽  
Author(s):  
U I Safronova ◽  
A A Vasilyev ◽  
R K Smith
Keyword(s):  
Transition Probabilities ◽  
Relativistic Effects ◽  
Radiative Transition ◽  
Branching Ratios ◽  
Transition Rates ◽  
Correlation Effects ◽  
Coupling Coefficients ◽  
Energy Matrix ◽  
Asymptotic Dependence ◽  
Intermediate Coupling

The relative intensities of dielectronic satellite lines determined by radiative transition probabilities and autoionization rates are calculated for the transitions 2lnl' – 1snl'', 2lnl' – 1s2l (n = 4–5, l' = 0–3, l'' = 0–3, l = 0–1) in He-like ions and for the transitions 1s2lnl' – 1s2nl'', 1s2lnl' – 1s22l (n = 4–5, l' =0–3, l'' = 0–3, l = 0–1) in Li-like ions, for all Z = 5–54, using the perturbation theory method (Z-expansion). Relativistic effects are taken into account using the Breit–Pauli operators. The asymptotic dependence on n of the energy matrix is discussed for 2lnl' and 1s2lnl' autoionizing states. The intermediate coupling coefficients obtained after diagonalization of the energy matrices are also studied. It was observed that these coefficients change very sharply with n and Z due to a redistribution of the contributions of relativistic and correlation effects. As a result, all other atomic characteristics (radiative and nonradiative transition rates, branching ratios, and relative intensity factor) display nonmonotonic Z- and n-dependencies with maxima and minima. PACS Nos.: 32.80D, 31.20G, 31.30J, 31.50

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