The Atomic Spectroscopic Data Center at the National Institute of Standards and Technology (NIST) Gaithersburg, MD 20899, USA is continuing its critical data compilation and bibliographical work. It has contributed all its evaluated transition probability material to a greatly expanded version 2.0 of the NIST atomic spectroscopic database, which is on the World Wide Web. This database contains about 50,000 transition probabilities with estimated uncertainties and may be accessed via links from the NIST Physics Laboratory WWW homepage at http://physics.nist.gov/

A comprehensive NIST bibliographical database on atomic transition probabilities, which now contains approximately 7500 entries, has been updated through July 2002, and is also available at the above-cited World Wide Web site. The current compilation work of the NIST atomic transition probabilities data center is centered on the evaluation and tabulation of numerical data for the lighter elements and on Fe I and Fe II. Work is in progress on hydrogen, helium, lithium, beryllium, boron, sodium, magnesium, aluminum, silicon, and sulfur. The tabulations include allowed (electric dipole) as well as forbidden (mainly magnetic dipole and electric quadrupole) lines.

The following major tabulations of transition probability data were published during the latest 3-year period:

1. The MCHF/MCDHF Collection was recently established and put on the Web by C. Froese Fischer et al. [79]. It contains a large number of transitions for Li-like through Al-like ions of various chemical elements, principally the lighter elements through atomic number Z = 30. The data include various types of electric-dipole forbidden lines and are obtained from sophisticated multi-configuration Hartree Fock (MCHF) or, for the heavier, more highly ionized species, from multi-configuration Dirac Hartree Fock (MCDHF) calculations. The tabulations provide data for fine-structure transitions and include other important spectroscopic data for each line, and are structured similar to the NIST tables.

2. The D.R.E.A.M. database, in short for "Database on Rare Earths at Mons University," [17] contains wavelengths, energy levels, oscillator strengths and radiative lifetimes for neutral, singly and multiply-ionized rare earth elements the lanthanides, with atomic numbers 57  Z  71. Presently, it contains about 55 000 lines for 23 ions, mostly for singly and doubly charged species, and further extensions are planned for the near future. It is also available on the Web.

3. Atomic spectral tables for numerous ions of Ne, Mg, Si, and S in the 10 Å to 170 Å region have been compiled by Podobedova et al. [145] These tables, containing about 3200 lines, were specifically prepared for x-ray space observatories, such as Chandra.

4. The NIST data center recently published a 632-page volume of spectral data for highly ionized atoms of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Kr, and Mo as Monograph 8 of the Journal of Physical and Chemical Reference Data [161]. This volume contains atomic transition probabilities for a substantial fraction of the 16 000 spectral lines tabulated in this book. It is planned to put these data on the Web.

5. Transition probabilities for the resonance lines of heavier elements have been compiled by Morton [123]. He has tabulated about 150 lines of the elements Ge (Z = 32) through Bi (Z = 83) plus some data for Tc, Th, and U.

6. The fourth edition of Allen’s widely used Astrophysical Quantities handbook [51] contains a chapter on "Spectra" by Cowley et al., which lists 270 oscillator strengths for prominent lines of numerous astrophysically important spectra and about another 160 A-values for magnetic dipole and electric quadrupole (forbidden) transitions.

7. A few other atomic databases have recently been established that contain transition probability data, but are of a more general nature. The emphasis, e.g., for the CHIANTI [102] and X-Star [92] databases, is on photoionization and collision rate data. The transition probability material in these tables is mostly taken from other databases. The "Plasma-Gate" internet collection of atomic databases by Y. Ralchenko [151] provides a complete listing of all atomic databases.

Some active ongoing experimental and theoretical projects are:

1. The FERRUM Project, which is an experimental effort to obtain highly precise f-values for Fe II. This has been recently reviewed in detail by S. Johansson [90].

2. Emission (branching ratio) and lifetime measurements for rare-earth spectra, by J. Lawler et al. [61,62,63, 70, 104,105,106, 177], done with hollow cathodes and Penning discharges, and the laser-induced fluorescence method.

3. Calculations and lifetime measurements of numerous rare-earth transitions, especially for singly- and doubly-charged ions, by Biemont, Garnir, Palmeri, Quinet, Svanberg, and co-workers [10,11, 13,14,15, 18, 70, 111, 140,141, 149, 187,188,189].

Also, the proceedings of the 7^th International Colloquium on Atomic Spectra and Oscillator Strengths (ASOS 7) [87] contain several informative review articles on major recent work. We note that much of the ongoing activity has shifted to heavier elements, including the rare earths.

The remaining part of this report is a bibliography of selected recent literature references, which contain new transition probability data of astrophysical interest produced during the last three-year period. Thus, this new selected bibliography continues where the last working group left off. As in the previous reports, the bibliographical material is ordered with respect to element and stage of ionization. Table 1 provides an overview of the bibliographical data by spectrum. We were selective in our choice of these references, i.e., all papers had to contain a significant amount of numerical data, normally for more than ten spectral lines. The references are identified by a running number, which refers to the general reference list at the end of this report. In the general reference list, the literature is ordered alphabetically according to the first author, and each reference contains one or more code letters indicating the method applied by the authors. These code letters are defined as follows:  

Theoretical Methods:

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Online: May 1997   -   Last update: June 2003