Finally, 1,593 structures of 64 water molecules originally calculated at the revPBE0-D3 level of theory and periodic boundary conditions were taken from Cheng et al. as provided. Since the set contains five structures with duplicate atomic positions these were removed from the dataset, resulting in 1,588 unique structures. The energies and forces for these structures were recomputed at the RPBE-D3 46,47 level of theory using VASP version 6.4.2. The hard PAW potential setups provided by the VASP package were used, with the cutoff energy set to 850 eV, the width for Gaussian smearing set to 0.05 eV and solely the Γ-point of the Brillouin zone being sampled. Following the results reported in Ref. 48, D3 corrections have been computed with the zero damping scheme.