where the second term on the right-hand side (RHS) is the potential difference due to 𝜎 free with 𝛿 IHP and 𝜖 IHP being the thickness and the dielectric permittivity of the space between the metal and the IHP, respectively. The third and fourth term on the RHS denote the potential difference due to the chemisorption-induced dipoles and the first-layer water dipoles, respectively, which are modeled below.