Techniques for the calculation of atomic structures and radiative data including relativistic corrections
TL;DR: Superstructure as mentioned in this paper is a general-purpose automatic atomic-structure program that uses multi-configuration type expansions to calculate term energies, intermediate-coupling energy levels, term coupling coefficients, and cascade coefficients.
About: This article is published in Computer Physics Communications.The article was published on 1974-11-01. It has received 781 citations till now. The article focuses on the topics: Matrix (mathematics) & Slater determinant.
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TL;DR: In this paper, a complete software package for the computation of various atomic data such as energy levels; radiative transition; collisional excitation; ionization by electron impact, photoionizatio...
Abstract: We describe a complete software package for the computation of various atomic data such as energy levels; radiative transition; collisional excitation; ionization by electron impact, photoionizatio...
1,055 citations
TL;DR: RMATRX1 as mentioned in this paper is a general program to calculate atomic continuum processes using the R -matrix method, including electronatom and electron-ion scattering, and radiative processes such as bound-bound transitions, photoionization and polarizabilities.
679 citations
TL;DR: In this article, the magnetic-dipole probabilities for carbon-like and oxygen-like ions were calculated up to atomic number Z = 12, including relativistic corrections to the magnetic dipole operator.
Abstract: The magnetic-dipole probabilities for the D-1(2)-P-3(2) and D-1(2)-P-3(1) transitions in carbon-like and oxygen-like ions are calculated up to atomic number Z = 12, including relativistic corrections to the magnetic dipole operator. The ratio of the probabilities for these two transitions is found to change by up to 5 per cent compared with previous theoretical work, none of which included these relativistic corrections, with the effect being largest for the near neutral ions. The transition probability ratio for the [O III] 5007 and 4959 Angstrom lines is found to be 3.01, implying an intensity ratio of 2.98, in significantly better agreement with the observed ratio than the earlier theoretical work.
539 citations
TL;DR: In this article, the authors present an approach for constructing detailed atmospheric models and synthetic spectra for hot luminous stars, which takes into account the effects of NLTE and radiation driven winds properly.
Abstract: Spectral analysis of hot luminous stars requires adequate model atmospheres which take into account the effects of NLTE and radiation driven winds properly. Here we present significant improvements of our approach in constructing detailed atmospheric models and synthetic spectra for hot luminous stars. Moreover, as we regard our solution method in its present stage already as a standard procedure, we make our program package WM- basic available to the community (download is possible from the URL given below). The most important model improvements towards a realistic description of stationary wind models concern: (i) A sophisticated and consistent description of line blocking and blanketing. Our solution concept to this problem renders the line blocking influence on the ionizing fluxes emerging from the atmospheres of hot stars - mainly the spectral ranges of the EUV and the UV are affected - in identical quality as the synthetic high resolution spectra representing the observable region. In addition, the line blanketing effect is properly accounted for in the energy balance. (ii) The atomic data archive which has been improved and enhanced considerably, providing the basis for a detailed multilevel NLTE treatment of the metal ions (from C to Zn) and an adequate representation of line blocking and the radiative line acceleration. (iii) A revised inclusion of EUV and X-ray radiation produced by cooling zones which originate from the simu- lation of shock heated matter. This new tool not only provides an easy-to-use method for O-star diagnostics, whereby physical constraints on the properties of stellar winds, stellar parameters, and abundances can be obtained via a comparison of observed and synthetic spectra, but also allows the astrophysically important information about the ionizing fluxes of hot stars to be determined automatically. Results illustrating this are discussed by means of a basic model grid calculated for O-stars with solar metallicity. To further demonstrate the astrophysical potential of our new method, we first provide a detailed spectral diagnostic determination of the stellar parameters, the wind parameters, and the abundances by an exemplary application to one of our grid-stars, the O9.5Ia O-supergiant α Cam. Our abundance determinations of the light elements indicate that these deviate considerably from the solar values.
517 citations
Cites methods from "Techniques for the calculation of a..."
...This has been done using the Superstructure program (Eissner et al. 1974; Nussbaumer and Storey 1978), which employs the configuration-interaction approximation to determine wave functions and radiative data....
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TL;DR: The CHIANTI database as mentioned in this paper provides a set of atomic data for the interpretation of astrophysical spectra emitted by collisionally dominated, high temperature, optically thin sources.
Abstract: Aims. The goal of the CHIANTI atomic database is to provide a set of atomic data for the interpretation of astrophysical spectra emitted by collisionally dominated, high temperature, optically thin sources. Methods. A complete set of ground level ionization and recombination rate coefficients has been assembled for all atoms and ions of the elements of H through Zn and inserted into the latest version of the CHIANTI database, CHIANTI 6. Ionization rate coefficients are taken from the recent work of Dere (2007, A&A, 466, 771) and recombination rates from a variety of sources in the literature. These new rate coefficients have allowed the calculation of a new set of ionization equilibria and radiative loss rate coefficients. For some ions, such as Fe viii and Fe ix, there are significant differences from previous calculations. In addition, existing atomic parameters have been revised and new atomic parameters inserted into the database. Results. For each ion in the CHIANTI database, elemental abundances, ionization potentials, atomic energy levels, radiative rates, electron and proton collisional rate coefficients, ionization and recombination rate coefficients, and collisional ionization equilibrium populations are provided. In addition, parameters for the calculation of the continuum due to bremsstrahlung, radiative recombination and two-photon decay are provided. A suite of programs written in the Interactive Data Language (IDL) are available to calculate line and continuum emissivities and other properties. All data and programs are freely available at http://wwwsolar.nrl.navy.mil/ chianti
513 citations
Cites methods from "Techniques for the calculation of a..."
...Electron impact excitation rate coefficients were calculated in the Distorted Wave approximation with the UCL suite of codes (Eissner et al. 1974; Eissner 1998)....
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References
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01 Jan 1935
TL;DR: In this paper, the quantum mechanical method is applied to the theory of complex spectra and the Russell-Saunders case is used to obtain the energy levels of one-electron spectra.
Abstract: 1. Introduction 2. The quantum mechanical method 3. Angular momentum 4. The theory of radiation 5. One-electron spectra 6. The central-field approximation 7. The Russell-Saunders case: energy levels 8. The Russell-Saunders case: eigenfunctions 9. The Russell-Saunders case: line strengths 10. Coupling 11. Intermediate coupling 12. Transformations in the theory of complex spectra 13. Configurations containing almost closed shells. X-rays 14. Central fields 15. Configuration interaction 16. The Zeeman effect 17. The Stark effect 18. The nucleus in atomic spectra Appendix. Universal constants and natural atomic units.
2,607 citations
Book•
01 Jan 1935
TL;DR: In this paper, the quantum mechanical method is applied to the theory of complex spectra and the Russell-Saunders case is used to obtain the energy levels of one-electron spectra.
Abstract: 1. Introduction 2. The quantum mechanical method 3. Angular momentum 4. The theory of radiation 5. One-electron spectra 6. The central-field approximation 7. The Russell-Saunders case: energy levels 8. The Russell-Saunders case: eigenfunctions 9. The Russell-Saunders case: line strengths 10. Coupling 11. Intermediate coupling 12. Transformations in the theory of complex spectra 13. Configurations containing almost closed shells. X-rays 14. Central fields 15. Configuration interaction 16. The Zeeman effect 17. The Stark effect 18. The nucleus in atomic spectra Appendix. Universal constants and natural atomic units.
2,552 citations
TL;DR: In this article, the state of the art in relativistic calculation of atomic structures is surveyed and the theory is modelled on the practice in non-relativistic calculations, using many-particle wave functions built from Dirac central field spinors.
Abstract: The current state of the art in relativistic calculation of atomic structures is surveyed. The theory is modelled on the practice in non-relativistic calculations, using many-particle wave functions built from Dirac central field spinors. The Hamiltonian includes quantum electrodynamic effects in the form of the Breit approximation for the interaction energy of two electrons. Within the limits for which this is valid, it is possible to construct matrices for one- and two-particle operators and hence to perform atomic structure calculations which automatically include the major relativistic effects. The theory can be greatly simplified by using Racah's tensor operators. Major applications have utilized the Hartree or Hartree-Fock methods, and the relevant equations are formulated in detail. Numerical Hartree-Fock solutions for the average of the ground configuration have now been obtained for most elements with atomic number less than 103, and some solutions have also been obtained for ions. The s...
640 citations