This is a compilation of approximately 1.72 million allowed, intercombination and forbidden atomic transitions with wavelengths in the range from 0.6 Å to 1000 µm. It's primary intention is to allow the identification of observed atomic absorption or emission features. The wavelengths in this list are all calculated from the difference between the energy of the upper and lower level of the transition (except for hydrogenic lines, which are a weighted average of all the fine structure components). Only a very limited attempt has been made to include observed wavelengths.
When attempting to identify an observed line, usually many possible candidates can be found in this list. In order to facilitate narrowing down the number of possible identifications a selection tool is presented which allows imposing, apart from the wavelength, several additional criteria.
The following documentation is available:
The author kindly thanks the following people (in alphabetical order) who contributed to this list by providing data and/or helpful insights:
K.M. Aggarwal, M.A. Bautista, C.F. Fischer (MCHF/MCDHF database), R. Kisielius, R.L. Kurucz, (Kurucz web site), S.N. Nahar (NORAD-Atomic-Data), M.J. Seaton, T. Sochi, D.A. Verner.
The current development of the atomic line list is described in van Hoof, P.A.M., 2018, Galaxies, 6, 63. Please cite this paper when you use any data from this list.
The atomic line list has undergone extensive development in the past years. The software generating the line list, as well as the program doing the line selection for the web page have been replaced by 12,000 lines of new C++ code. All this work was necessary to restructure the internal data files and facilitate future upgrades of the line list. The primary goal will be to make the list complete for all elements, as far as data are available. This release starts this process by making the list complete for all 4th row elements. Future releases will start adding 5th, 6th, and 7th row elements. The second goal is to add more transition probability data from additional sources. Finally, an effort will be made to include observed wavelengths, especially for forbidden transitions. These are the most important user-visible changes that are implemented in this version:
|The request form has been improved. An option for specifying the radial velocity of the emitting source has been added, thus making Doppler-shift corrections by hand unnecessary. Multiplet searches can now be done by simply clicking on the term field in the output. It is now possible to select lines based on the transition probability of the line. The maximum number of lines in the output has been increased to 5000. Multiple wavelength ranges can now be supplied at once. Plain and LaTeX mode now produce truly HTML-free output when saved to disk.|
|The search tool has been improved. The output will now always be correctly sorted, the search criteria are repeated in the output for later reference, and a few minor bugs have been solved.|
|Selection rules for intercombination, magnetic dipole (M1) and electric quadrupole (E2) transitions have been improved. Magnetic quadrupole (M2) and electric octupole (E3) transitions have been added to the list. This makes the list more accurate and complete.|
|The theory for calculating level energies of hydrogenic ions has been fully updated following Section IV of Mohr, Taylor, & Newell, 2008, Rev. Mod. Phys. 80, 633. Furthermore, data for the following ions have been updated/amended: He I, Be II, Be III, C II, C IV, Ne IV, Ca III, Mn VII, Fe II, Fe III, Fe V, Ni III, Ni X. Data for the elements Gallium through Krypton have been added. Transition probability data have been added from the NIST ASD v3.0 database, the MCHF/MCDHF collection (C.F. Fischer et al.), the second generation of semi-emperical log(gf) values by R.L. Kurucz (only partially complete), Taha Sochi (for C II), Romas Kisielius (for Zn II) and various sources for Fe III.|
The Atomic Line List is hosted by
Department of Physics & Astronomy
University of Kentucky
and is maintained by
Peter van Hoof
Royal Observatory of Belgium