I am looking for a database, in which the experimental ionization energies (and e.g. heat of formation) of atoms and diatomic molecules are listed as files. If it comes with a Python package, that would even better.

I found the Pitt Quantum Repository, but there seem to be only theoretical values.

  • $\begingroup$ CRC handbook of chemistry and physics lists IEs of elements, atomic and several molecular ions. Also, have a look at Resources for learning Chemistry. $\endgroup$
    – andselisk
    Oct 20, 2019 at 14:20
  • $\begingroup$ Ah. The good old rubber bible. No chemistry shelf is complete without it. :-) $\endgroup$
    – Gwyn
    Jul 1, 2020 at 18:26

1 Answer 1


NIST Atomic Spectra Database has the atom part. Not sure about molecules. https://physics.nist.gov/PhysRefData/ASD/ionEnergy.html


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