Special Issue "Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities"

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A special issue of Atoms (ISSN 2218-2004).

Deadline for manuscript submissions: closed (31 January 2014)

Special Issue Editors

Guest Editor
Prof. Dr. Per Jönsson

School of Technology, Applied Mathematics Group, Malmö University, Sweden
Website | E-Mail
Guest Editor
Dr. Alexander Kramida

Atomic Spectroscopy Group, Quantum Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, USA
Website | E-Mail
Phone: 301-975-8074
Interests: evaluation of energy levels, wavelengths, and transition probabilities in the spectra of beryllium and neon and spectra of all stages of ionization of tungsten
Guest Editor
Dr. Hyun-Kyung Chung

International Atomic Energy Agency, Atomic and Molecular Data Unit, Nuclear Data Section, P.O. Box 100, A-1400 Vienna, Austria
E-Mail
Phone: +43 1 2600 21729
Fax: +43 1 26007
Interests: atomic, molecular and plasma-surface interaction data for fusion applications; atomic processes in plasmas; non-LTE kinetics in plasmas; radiative properties of hot dense matter; plasma spectroscopy modeling

Special Issue Information

Dear Colleagues,

There exist several codes in the atomic physics community to generate atomic structure and transition probabilities freely and readily distributed to researchers outside atomic physics community, in plasma, astrophysical or nuclear physics communities. Users take these atomic physics codes to generate the necessary atomic data or modify the codes for their own applications. However, there has been very little effort to validate and verify the data sets generated by non-expert users.

In a recent IAEA meeting, researchers who develop the atomic physics codes met to discuss procedures to validate data sets generated by these distributed atomic physics codes. They agreed to implement and document the procedures to insure and validate code-generated data for non-experts in their codes.

This special issue aims to document each code’s approach and procedure to critically assess the uncertainties of theoretical atomic data. It will have a broad impact, not only for the atomic physics community, but also for other communities interested in high quality atomic data.

Prof. Dr. Per Jönsson
Dr. Alexander Kramida
Dr. Hyun-Kyung Chung
Guest Editors

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Atoms is an international peer-reviewed Open Access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There will be no article processing charge (APC) for this special issue of Atoms.


Keywords

  • atomic structure
  • atomic transition probabilities
  • data validation
  • critical assessment of theoretical atomic data
  • atomic code development
  • atomic code validation
  • uncertainties of atomic data

Published Papers (8 papers)

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Editorial

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Open AccessEditorial Notes on Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities
Atoms 2013, 1(3), 14-16; doi:10.3390/atoms1030014
Received: 29 July 2013 / Accepted: 29 July 2013 / Published: 8 August 2013
PDF Full-text (154 KB) | HTML Full-text | XML Full-text
Abstract
Atomic structure and transition probabilities are fundamental physical data required in many fields of science and technology. Atomic physics codes are freely available to other community users to generate atomic data for their interest, but the quality of these data is rarely verified.
[...] Read more.
Atomic structure and transition probabilities are fundamental physical data required in many fields of science and technology. Atomic physics codes are freely available to other community users to generate atomic data for their interest, but the quality of these data is rarely verified. This special issue addresses estimation of uncertainties in atomic structure and transition probability calculations, and discusses methods and strategies to assess and ensure the quality of theoretical atomic data. Full article
Open AccessEditorial Special Issue on Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities
Atoms 2013, 1(2), 13; doi:10.3390/atoms1020013
Received: 19 June 2013 / Accepted: 20 June 2013 / Published: 21 June 2013
PDF Full-text (83 KB) | HTML Full-text | XML Full-text
Abstract
There exist several codes in the atomic physics community to generate atomic structure and transition probabilities freely and readily distributed to researchers outside atomic physics community, in plasma, astrophysical or nuclear physics communities. Users take these atomic physics codes to generate the necessary
[...] Read more.
There exist several codes in the atomic physics community to generate atomic structure and transition probabilities freely and readily distributed to researchers outside atomic physics community, in plasma, astrophysical or nuclear physics communities. Users take these atomic physics codes to generate the necessary atomic data or modify the codes for their own applications. However, there has been very little effort to validate and verify the data sets generated by non-expert users. [...] Full article

Research

Jump to: Editorial, Review

Open AccessArticle Estimating Relative Uncertainty of Radiative Transition Rates
Atoms 2014, 2(4), 382-390; doi:10.3390/atoms2040382
Received: 31 January 2014 / Revised: 16 September 2014 / Accepted: 9 October 2014 / Published: 25 November 2014
Cited by 1 | PDF Full-text (242 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We consider a method to estimate relative uncertainties of radiative transition rates in an atomic spectrum. Few of these many transitions have had their rates determined by more than two reference-quality sources. One could estimate uncertainties for each transition, but analyses with only
[...] Read more.
We consider a method to estimate relative uncertainties of radiative transition rates in an atomic spectrum. Few of these many transitions have had their rates determined by more than two reference-quality sources. One could estimate uncertainties for each transition, but analyses with only one degree of freedom are generally fraught with difficulties. We pursue a way to empirically combine the limited uncertainty information in each of the many transitions. We “pool” a dimensionless measure of relative dispersion, the “Coefficient of Variation of the mean,” \(C_{V}^{n} \equiv s/(\bar{x}\sqrt{n})\). Here, for each transition rate, “s” is the standard deviation, and “\(\bar{x}\)” is the mean of “n” independent data sources. \(C_{V}^{n}\) is bounded by zero and one whenever the determined quantity is intrinsically positive.) We scatter-plot the \(C_{V}^{n} \)as a function of the “line strength” (here a more useful radiative transition rate than transition probability). We find a curve through comparable \(C_{V}^{n} \)as that envelops a specified percentage of the \(C_{V}^{n} \)s (e.g. 95%). We take this curve to represent the expanded relative uncertainty of the mean. The method is most advantageous when the number of determined transition rates is large while the number of independent determinations per transition is small. The transition rate data of Na III serves as an example. Full article
Open AccessArticle AtomPy: An Open Atomic Data Curation Environment for Astrophysical Applications
Atoms 2014, 2(2), 123-156; doi:10.3390/atoms2020123
Received: 6 January 2014 / Revised: 7 April 2014 / Accepted: 8 April 2014 / Published: 2 May 2014
Cited by 3 | PDF Full-text (2768 KB) | HTML Full-text | XML Full-text
Abstract
We present a cloud-computing environment, referred to as AtomPy, based on Google-Drive Sheets and Pandas (Python Data Analysis Library) DataFrames to promote community-driven curation of atomic data for astrophysical applications, a stage beyond database development. The atomic model for each ionic species is
[...] Read more.
We present a cloud-computing environment, referred to as AtomPy, based on Google-Drive Sheets and Pandas (Python Data Analysis Library) DataFrames to promote community-driven curation of atomic data for astrophysical applications, a stage beyond database development. The atomic model for each ionic species is contained in a multi-sheet workbook, tabulating representative sets of energy levels, A-values and electron impact effective collision strengths from different sources. The relevant issues that AtomPy intends to address are: (i) data quality by allowing open access to both data producers and users; (ii) comparisons of different datasets to facilitate accuracy assessments; (iii) downloading to local data structures (i.e., Pandas DataFrames) for further manipulation and analysis by prospective users; and (iv) data preservation by avoiding the discard of outdated sets. Data processing workflows are implemented by means of IPython Notebooks, and collaborative software developments are encouraged and managed within the GitHub social network. The facilities of AtomPy are illustrated with the critical assessment of the transition probabilities for ions in the hydrogen and helium isoelectronic sequences with atomic number Z ≤ 10. Full article
Open AccessArticle Assessing Uncertainties of Theoretical Atomic Transition Probabilities with Monte Carlo Random Trials
Atoms 2014, 2(2), 86-122; doi:10.3390/atoms2020086
Received: 31 January 2014 / Revised: 20 March 2014 / Accepted: 2 April 2014 / Published: 14 April 2014
Cited by 3 | PDF Full-text (832 KB) | HTML Full-text | XML Full-text
Abstract
This paper suggests a method of evaluation of uncertainties in calculated transition probabilities by randomly varying parameters of an atomic code and comparing the results. A control code has been written to randomly vary the input parameters with a normal statistical distribution around
[...] Read more.
This paper suggests a method of evaluation of uncertainties in calculated transition probabilities by randomly varying parameters of an atomic code and comparing the results. A control code has been written to randomly vary the input parameters with a normal statistical distribution around initial values with a certain standard deviation. For this particular implementation, Cowan’s suite of atomic codes (R.D. Cowan, The Theory of Atomic Structure and Spectra, Berkeley, CA: University of California Press, 1981) was used to calculate radiative rates of magnetic-dipole and electric-quadrupole transitions within the ground configuration of titanium-like iron, Fe V. The Slater parameters used in the calculations were adjusted to fit experimental energy levels with Cowan’s least-squares fitting program, RCE. The standard deviations of the fitted parameters were used as input of the control code providing the distribution widths of random trials for these parameters. Propagation of errors through the matrix diagonalization and summation of basis state expansions leads to significant variations in the resulting transition rates. These variations vastly differ in their magnitude for different transitions, depending on their sensitivity to errors in parameters. With this method, the rate uncertainty can be individually assessed for each calculated transition. Full article
Open AccessArticle Evaluation and Comparison of the Configuration Interaction Calculations for Complex Atoms
Atoms 2014, 2(1), 1-14; doi:10.3390/atoms2010001
Received: 24 January 2014 / Revised: 10 March 2014 / Accepted: 12 March 2014 / Published: 19 March 2014
Cited by 11 | PDF Full-text (308 KB) | HTML Full-text | XML Full-text
Abstract
Configuration interaction (CI) methods are the method of choice for the determination of wave functions for complex atomic systems from which a variety of atomic properties may be computed. When applied to highly ionized atoms, where few, if any, energy levels from observed
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Configuration interaction (CI) methods are the method of choice for the determination of wave functions for complex atomic systems from which a variety of atomic properties may be computed. When applied to highly ionized atoms, where few, if any, energy levels from observed wavelengths are available, the question arises as to how a calculation may be evaluated. Many different codes are available for such calculations. Agreement between the results from different codes in itself is not a check on accuracy, but may be due to a similarity in the computational procedures. This paper reviews basic theory, which, when applied in a systematic manner, can be the basis for the evaluation of accuracy. Results will be illustrated in the study of 4s24p5 (odd) and 4s24p44d (even) levels in W39+ and the transitions between them. Full article
Open AccessArticle Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities: An Experimenter’s View
Atoms 2014, 2(1), 15-85; doi:10.3390/atoms2010015
Received: 25 January 2014 / Revised: 5 March 2014 / Accepted: 5 March 2014 / Published: 19 March 2014
Cited by 5 | PDF Full-text (939 KB) | HTML Full-text | XML Full-text
Abstract
The interpretation of atomic observations by theory and the testing of computational predictions by experiment are interactive processes. It is necessary to gain experience with “the other side” before claims of achievement can be validated and judged. The discussion covers some general problems
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The interpretation of atomic observations by theory and the testing of computational predictions by experiment are interactive processes. It is necessary to gain experience with “the other side” before claims of achievement can be validated and judged. The discussion covers some general problems in the field as well as many specific examples, mostly organized by isoelectronic sequence, of what level of accuracy recently has been reached or which atomic structure or level lifetime problem needs more attention. Full article

Review

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Open AccessReview Validation and Implementation of Uncertainty Estimates of Calculated Transition Rates
Atoms 2014, 2(2), 215-224; doi:10.3390/atoms2020215
Received: 31 January 2014 / Revised: 29 April 2014 / Accepted: 2 May 2014 / Published: 15 May 2014
Cited by 9 | PDF Full-text (862 KB) | HTML Full-text | XML Full-text
Abstract
Uncertainties of calculated transition rates in LS-allowed electric dipole transitions in boron-like O IV and carbon-like Fe XXI are estimated using an approach in which differences in line strengths calculated in length and velocity gauges are utilized. Estimated uncertainties are compared and validated
[...] Read more.
Uncertainties of calculated transition rates in LS-allowed electric dipole transitions in boron-like O IV and carbon-like Fe XXI are estimated using an approach in which differences in line strengths calculated in length and velocity gauges are utilized. Estimated uncertainties are compared and validated against several high-quality theoretical data sets in O IV, and implemented in large scale calculations in Fe XXI. Full article

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.


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