and the capacitance value obtained from the finite-field DFTMD simulations, one gets z im -z a for Au(111) is about 1.35 Å instead. This value is almost the same as the assumed position of image plane for Au(111). In addition, we have also seen the adsorption of Na ions in the semi-classical simulations with z im -z a = 1.22 Å (Fig. in the Supporting Information), similar to what was reported previously. This suggests a reparameterization of force fields for Na ions or the introducing of explicit polarizability is probably needed to restore the correct molecular structure at the electrified interface in semi-classical MD simulations. Nevertheless, it is clear now that the origin of this enhancement in the total capacitance have little to do with the adsorption of Na ions but come from the electronic response of gold electrode. Therefore, what is shown here provides a stepping stone for understanding the unexpected high capacitance of single Au nanoparticle reported experimentally. We have also observed very rapid Cl adsorption on the Au(111) surface at PZC (D = 0) and at polarized Au(100) (D = 0.018 au). Fig. shows the change in position of the Cl ions over the DFTMD trajectories. The Cl starts a few Å from the surface and adsorbs within a few ps and becomes stationary at the surface for the rest of the simulation. This comes in line with the "immeasurably high" adsorption rate deduced from the impedance spectroscopy. The observed fast Cl adsorption on the Au(111) surface at PZC instead of the Au(100) at PZC is likely due to a higher surface potential (therefore work function) of Au(111) as compared to that of Au(100). The opposite happened to polarized Au(111) and Au(100) surfaces are related to the interfacial water structure (see below).