To obtain the information of products of water splitting, we compute the Hirshfeld charge 60 of H and O atoms in real time. The amount of Hirshfeld charge may be underestimated because the electron loss when they reach the absorbing boundary. The results in Figure In order to understand the reaction mechanism, we calculate the time-evolved population of AB state of H 2 O molecule and LUMO of hybrid system in Figure . We observe that the photo-induced electron transfer taking place from the metal to the AB states of H 2 O molecule, indicating that the water splitting occurs when the AB states are populated by the electrons.