The Atomic Line List v2.04

This is a compilation of approximately 923,000 allowed, intercombination and forbidden atomic transitions with wavelengths in the range from 0.5 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. No attempt has been made to include observed wavelengths. Most of the atomic energy level data have been taken from the Atomic Spectra Database provided by the National Institute of Standards and Technology (NIST).

A beta version of the next release of the atomic line list can be found here. This version includes elements up to krypton and also many new data sources.

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 this line list, or any large part of it, is only allowed with permission of the author.

Please acknowledge use of the Atomic Line List (including the URL) in each paper that contains data from this list.

The author kindly thanks the following persons (in alphabetical order) who supplied data compiled in this list:

M.A. Bautista, S.N. Nahar, M.J. Seaton, D.A. Verner.

Recent Developments

New!The line data for C II, III and IV have been extended.
New!The line data for chlorine and argon is complete now.
New!The transition probabilities for Ne I calculated by Seaton have been included.
New!Transition probabilities calculated using the Coulomb approximation have been added for the helium, lithium, sodium and potassium iso-electronic sequences.

Selection Criteria

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

Wavelength range: Unit: Type:
(e.g. 6500-6600, or 6545+/-1)
Wavl. accuracy (U.L. in %):


(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 abundance: Depl. factor:

Lower level energy range: Unit:
Upper level energy range:
Maximum for principal quantum number n:

Select a specific multiplet:
(e.g. b3F4-z3Go; query is case sensitive)

Transitions: All Types Nebular Select: E1 IC M1 E2
Fine structure of transitions in hydrogen-like spectra: Suppress Show
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 fik as S as log(gf)
Transition probability flags
Level energies
Literature references
Output mode: plain latex

Version 2.04 of the line list was created: Oct 19, 1999.

The Atomic Line List is hosted by the

Department of Physics and 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.vanhoof AT oma DOT be