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