Training datasets are AIMDEF trajectories of ref 17. More details on the AIMDEF calculations can be found in that reference and in Sec. 3. Here it suffices to say that, all used trajectories were run with a modified version of the Vienna Simulation Package (VASP), using DFT in the generalized gradient approximation to the exchange-correlation functional by Perdew-Becke-Ernzerhof (PBE) and employing a plane wave basis. All trajectories used