skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Atomic Data for Opacity Calculations

Abstract

Theoretical methods, emphasizing on various physical effects with a variety of accuracy, have been employed to obtain the atomic data for opacity calculations. For energy levels and oscillator strength, one- and multi- configurational self-consistent schemes in both full relativistic and non-relativistic forms have been used to show how the detailed treatment of the electronic correlations and the relativistic effects, affects the finally calculated opacity. Quantum mechanical and semi-classical approaches have been used to deal with the electron impact broadening of the spectral lines. One channel and multi-channel close-coupling approaches have been applied in the calculations of the photoionization cross sections. With the channel coupling, we have shown the importance of the autoionization effects for the transmission spectra. As examples, x-ray transmission spectra and the spectra-resolved opacities of Al, Fe, and Au are presented based on the so-called detailed-term (or level)-accounting treatments for the atomic data.

Authors:
 [1]
  1. Department of Physics, National University of Defense Technology, Changsha 410073 (China)
Publication Date:
OSTI Identifier:
21056926
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 901; Journal Issue: 1; Conference: ICAMDATA: 5. international conference on atomic and molecular data and their applications, Meudon (France), 15-19 Oct 2006; Other Information: DOI: 10.1063/1.2727372; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ABSORPTION SPECTRA; AUTOIONIZATION; CORRELATIONS; COUPLING; CROSS SECTIONS; DATA COMPILATION; ELECTRONS; ENERGY LEVELS; LINE BROADENING; OPACITY; OSCILLATOR STRENGTHS; PHOTOIONIZATION; QUANTUM MECHANICS; RELATIVISTIC RANGE; X RADIATION; X-RAY SPECTRA

Citation Formats

Yuan Jianmin. Atomic Data for Opacity Calculations. United States: N. p., 2007. Web. doi:10.1063/1.2727372.
Yuan Jianmin. Atomic Data for Opacity Calculations. United States. doi:10.1063/1.2727372.
Yuan Jianmin. Fri . "Atomic Data for Opacity Calculations". United States. doi:10.1063/1.2727372.
@article{osti_21056926,
title = {Atomic Data for Opacity Calculations},
author = {Yuan Jianmin},
abstractNote = {Theoretical methods, emphasizing on various physical effects with a variety of accuracy, have been employed to obtain the atomic data for opacity calculations. For energy levels and oscillator strength, one- and multi- configurational self-consistent schemes in both full relativistic and non-relativistic forms have been used to show how the detailed treatment of the electronic correlations and the relativistic effects, affects the finally calculated opacity. Quantum mechanical and semi-classical approaches have been used to deal with the electron impact broadening of the spectral lines. One channel and multi-channel close-coupling approaches have been applied in the calculations of the photoionization cross sections. With the channel coupling, we have shown the importance of the autoionization effects for the transmission spectra. As examples, x-ray transmission spectra and the spectra-resolved opacities of Al, Fe, and Au are presented based on the so-called detailed-term (or level)-accounting treatments for the atomic data.},
doi = {10.1063/1.2727372},
journal = {AIP Conference Proceedings},
number = 1,
volume = 901,
place = {United States},
year = {Fri Apr 06 00:00:00 EDT 2007},
month = {Fri Apr 06 00:00:00 EDT 2007}
}
  • A method is proposed for simulating resolved transition arrays of ionized atom spectra in full intermediate coupling. The wave number and intensity of each line in an array are picked at random from separated but correlated distributions. Even though each line is not exactly reproduced, this procedure yields the correct following characteristics of the supposedly symmetric array: total intensity; second and fourth moments of the distributions of unweighted wave numbers, of intensity-weighted wave numbers, and of transition amplitudes; numbers of lines and sums of intensities in consecutive narrow energy ranges. All the parameters of the distribution are obtained by meansmore » of compact formulas, or tabulated. Applications to the arrays 4{ital d}{sup 4}-4{ital d}{sup 3}5{ital p} of Pd{sup 6+} and 4{ital d}{sup 7}5{ital s}-4{ital d}{sup 7}5{ital p} of Cd{sup 4+} are presented. Comparison with the explicit results of the Slater-Condon method shows good agreement. It is proposed to use this method for fast and reliable computation of Rosseland means and other opacity properties.« less
  • Detailed Configuration Accounting methods for the calculation of X-Ray absorption of hot medium Z plasmas may sometimes treat the individual transition arrays as unresolved. An unresolved transition array is usually approximated by a gaussian profile whose centroid and width are given by analytic formulae to reproduce ab-initio central field calculations. A more realistic profile would extend the validity of the current computationally efficient approach into conditions where transition arrays are resolved, but would require additional information, such as the higher moments of the array. However, so closed form formulae for the higher moments of multi-open-subshell transition arrays have been derived,more » mainly due to their inherent complexity. As an alternative, we have investigated training Neural Networks as an efficient means to provide us with this information.« less