This convergence in ∆φ indicates a constant contribution from the bulk dielectric of liquid water in addition to the specific adsorption of H 2 O molecules on the surface. The binding energy threshold (see Figure ) of convergence thereby coincides with the condensation energy of H 2 O of 0.4 eV below which water interaction is more favorable than specific adsorption. We note that such a convergence is absent in the work by Li et al. , where deviation may be present due to stronger binding through the PBE-D3 functional and the missing systematic influence of the water-vacuum interface. The demonstrated correlation of n H 2 O per site and ∆φ AIMD allows for the prediction of the latter through the estimation of the former. An estimate of n H 2 O may be evaluated using a simple descriptor that can be obtained from inexpensive static DFT calculations in order to circumvent computationally expensive AIMD simulations. An intuitive choice in this regard would be the electronic binding energy of H 2 O in vacuum (∆E H 2 O ) which fulfills this requirement as shown in Figure . This descriptor has also been suggested by Li et al. as it works straight-forwardly for terrace sites. For the prediction of (211) step sites, a refined normalization ñH 2 O is required where we distinguish between contained terrace and step site contributions (see methods Equation ). This relation using ñH