Both the water layer and the topmost atomic Fe layer gain charge from the bulk Fe, with the total charge difference compared to the system without the water layer ranging from -0.27e to -0.59e, depending on the orientation of the water molecules. This is consistent with the moderate reactivity of iron in aqueous environments. orientations affect interfacial electronic properties, the density of states (DOS) analysis for the iron surface was presented in Figure . For the H-up configuration, the iron d-states distribution remains symmetric, closely resembling that of the clean iron surface (Figure in the supplementary materials (SM)), implying weak spin polarization and interaction with water. In contrast, the H-mix and H-down configurations exhibit asymmetric d-band distributions, suggesting stronger interactions between water and the iron surface. The weaker interaction of the H-up water configuration is further supported by its lower adsorption energy and greater water-surface distance, as shown in Table .