Water response Having discussed the peculiarities of the electronic excess charge distribution at Pt(111), we now focus on the detailed response of water within the three considered methods. The results are largely as expected: Both DFT methods agree in the density and orientation response, featuring the expected bilayer interfacial water structure with bias-dependent amounts of chemisorbed water . In contrast, the FF trajectory exhibits more generic e.g. reorientational response without present bilayer structure or chemisorbed molecules (see section S3 in the SI).