When identifying isolated observed spectral features or fitting complex observed spectra or even running complex numerical simulations, one needs a reliable, standard table of known wavelengths and other parameters like splitting, intensity relationships, etc.

Question: Where do Astronomers usually get their wavelengths? Are there a few favorite references where astronomers turn to look up standard, accepted values for spectral features?

Somewhat related:


1 Answer 1


Splatalogue is an excellent resource that allows you to search for spectral line transitions for a given atomic/molecular species within a specified wavelength range. It compiles data from a number of sources, including JPL, the Cologne Database for Molecular Spectroscopy (CDMS), and Lovas/NIST.

If you are looking for more detailed information than just the wavelengths, I recommended either going to CDMS directly, or using the Leiden Atomic And Molecular Database (LAMDA). This provides details such as Einstein A coefficients, energy levels and collisional data for a small number of key molecular species.

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    $\begingroup$ These are great, thanks! Do you know if Splatalog, CDMS or LAMDA are used by astronomers to look up standard, accepted values for spectral features? I haven't asked for a recommendation, I've asked for what sources astronomers usually use. $\endgroup$
    – uhoh
    Aug 14, 2021 at 14:28
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    $\begingroup$ @uhoh I am a PhD astrophysics student, so I can only speak for myself and colleagues. But yes, we use these tools regularly. For example, Splatalogue is very helpful when putting together a telescope proposal, to identify which lines lie within a particular spectral window. Data from CDMS/LAMDA is incorporated directly into computer models to allow the gas chemistry to be accurately simulated. $\endgroup$
    – lucas
    Aug 15, 2021 at 9:03
  • $\begingroup$ Then that sounds pretty conclusive, thanks! $\endgroup$
    – uhoh
    Aug 15, 2021 at 9:05

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