Following the procedure outlined in Ref. 43, the FE curves obtained from WTMD simulations at the DFTB3 level were perturbatively corrected using accurate Hamiltonians via MetaFEP. With this method, a restricted number of configurations (𝑁) are extracted from the WTMD trajectory and used to compute the single-point energies at a higher level of theory. In this way, the low-level FE (FELL) is used as a reference to reconstruct the target accurate potential (FEHL) by means of FE perturbation (FEP) according to the following relationship: