What is the best database for the identification of spectral lines? For instance, I have a red spectrum of A0 star and I would like to recognize the most prominent lines, where to find them? Many thanks.

EDIT: Why is O2 line not in NIST? It would be about 2676.99 A.

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source: http://www.spektros.de/sirius/sirius.html

After advice: How to install the database for molecules https://bitbucket.org/OES_muni/massiveoes/src/master/? I obtained the following error:

python setup.py develop
/home/linux/.local/lib/python2.7/site-packages/setuptools/dist.py:474: UserWarning: Normalizing '1.001' to '1.1'
running develop
error: can't create or remove files in install directory

The following error occurred while trying to add or remove files in the
installation directory:

    [Errno 13] Permission denied: '/usr/local/lib/python2.7/dist-packages/test-easy-install-547.write-test'

The installation directory you specified (via --install-dir, --prefix, or
the distutils default setting) was:


Perhaps your account does not have write access to this directory?  If the
installation directory is a system-owned directory, you may need to sign in
as the administrator or "root" account.  If you do not have administrative
access to this machine, you may wish to choose a different installation
directory, preferably one that is listed in your PYTHONPATH environment

For information on other options, you may wish to consult the
documentation at:


Please make the appropriate changes for your system and try again.
  • 3
    $\begingroup$ The NIST atomic spectra database. $\endgroup$
    – ProfRob
    Mar 16, 2021 at 13:21
  • 5
    $\begingroup$ To make the point more explicit: O2 is a molecule, so it doesn't show up in the atomic database $\endgroup$
    – llama
    Mar 16, 2021 at 17:29

2 Answers 2


There is the NIST Atomic Spectra Database where you could browse by elements. This the reverse approach, meaning that you have to first query element by element and then see which of the lines you find in the spectrum - that's how we used to do it in our labs during studies:

Screenshot of NIST Atomic Spectra Database

Then, there is another NIST site where you can enter up to 4 spectral lines in units of electron Volt to be identified:

NIST's 4 line helper screenshot

I am aware that there is also at least one old commercial software (some name starting with Win) to do that, running under Windows 3.1. There is also custom written C-code used by research groups working on the topic, but I have to dig to figure out whether these software is still available. All I found is a software called Spectrum Analyzer which I have not tested.

  • $\begingroup$ Thank you very much. I edited the question. I cannot find that line in a NIST database. I tried Spectrum Analyzer. For inbuilt examples, it works amazingly; however, after loading my spectrum, there was an error No lines have been found. $\endgroup$
    – Elena Greg
    Mar 16, 2021 at 13:15
  • 2
    $\begingroup$ @ElenaGreg same problem as why O2 isn't in the NIST database: Spectrum Analyzer only uses atomic transitions. They link to massiveOES for molecular ones on that page but it seems to be dead, here's another one bitbucket.org/OES_muni/massiveoes/src/master $\endgroup$
    – llama
    Mar 16, 2021 at 17:32
  • $\begingroup$ Thank you. Could you help me with installation, please? I added the problem to my question. $\endgroup$
    – Elena Greg
    Mar 17, 2021 at 21:32

Here is another alternative/supplement to NIST. The VALD atomic line database, which is specifically for astrophysical applications.

I believe this database does contain some molecular data too.


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