It is found that the change in RESP charges before and after adsorption is more significant in the case of Au(100) as compared to Au(111) (Fig. ). The percentage of partial charge transfer is about 50% for adsorbed Cl -on Au(100) and 20% for that on Au(111), and the latter can be related to the experimentally measured electrosorption valency of 0.4e for Cl - adsorption at gold electrode.