The Atomic Line List v2.05b21
Welcome to the atomic line list !

This is a beta version of the next release of the Atomic Line List. It has not been been fully tested and is likely to change without prior notice. It is being offered for testing purposes only. If you notice any problems with the content or the interface, please report these to the maintainer at the email listed at the bottom of this page.

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:

Please note that publication of the entire line list, or any large part of it, is only allowed with permission of the author.

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.

Constructing this web page would be impossible without the continued efforts of many people generating the energy level and transition probability data, and making them publicly available. Please consider acknowledging this effort by citing the original source(s) of the data as well!

Recent Developments

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 The software generating the line list, as well as the program doing the line selection for the web page have been replaced by 12,000 lines of new C++ code.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:

New! 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.
New! 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.
New! 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.
New!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.

Selection Criteria

All fields in the request form have default values and may be left unspecified

Wavelength range:

(e.g. 6500-6600, or 6545+/-1, the "-" or "+/-" symbols are optional)
(multiple queries, each on a separate line, are allowed)
Wavelength Unit: Type:
Radial velocity: vrad (in km/s) cosmological redshift z
A positive value means that the observed wavelength typed above
is redshifted w.r.t. the laboratory wavelengths in the output.
Min. relative wavl. accuracy:
Upper limit in percent.

(e.g. C II, or C II-IV, or C, or C-O; query is not case sensitive;
multiple lines of input are allowed)
Minimum line strength: Type:
Lines without atomic data: include exclude

Minimum abundance: Depl. factor:
Logarithmic number density, relative to log(H) = 12.
Lower level energy range: Unit:
Upper level energy range:
Maximum for principal quantum number n:

Transition types: All Types Nebular Select: E1 IC M1 E2 M2 E3
Transitions from auto-ionizing levels: Suppress Show

Customize Output

Output format (Check each item you want included in the output):

Wavelength accuracy
Transition type
Angular momentum: as J as g combine with term
Transition probability: as Aki as gkAki as fik as S as log(gf)
Level energies
Output mode: plain html latex

Maximum no. of output lines:

Version 2.05b21 of the line list was created: Nov 7, 2017.

The Atomic Line List is hosted by

University of Kentucky Department of Physics & Astronomy
University of Kentucky

and is maintained by

Peter van Hoof
Royal Observatory of Belgium
Ringlaan 3
1180 Brussel

Idea! Please send comments and suggestions to: p DOT vanhoof AT oma DOT be