Each cluster structure (XYZ Cartesian coordinates) in the databases has an associated electronic energy and, in some cases, also forces derived from electronic energy gradients. For ML modeling, the structure must have a suitable molecular representation (explained in sec. 2.3) since different XYZ coordinates can correspond to the same structure when translated, mirrored, or atom-wise permuted since XYZs are translation/rotation/atom-permutation noninvariant. Furthermore, relative energies (e.g., atomization or binding energies) are preferable to absolute electronic energies, as they exhibit a lower spread of the modeled values between different clusters, which simplifies the data fitting. Therefore, we use the electronic binding energies ∆E, i.e., the energies released upon cluster (C) formation from its monomers (M) at energy-minimum configuration