Adsorption of radioiodine on Cu₂O surfaces: A first-principles density functional study

The adsorption behavior of radioiodine (I₂) molecules on three different low-index surfaces of cuprous oxide (Cu₂O) was systematically investigated using first-principles density functional calculations with periodic slab models. The role of typical surface adsorption sites was evaluated by calculating structural parameters of the adsorption configurations and energy features. Moderate geometry relaxation of the three low-index surfaces was observed. The results of geometry optimization and total energy calculations indicated that the Cu₂O(100) and 111 surfaces exhibit higher reactivity towards I2 adsorption than the Cu₂O(110) surface. The surface oxygen site (O_S) was determined to be the most favorable adsorption site on the Cu₂O(100) surface, while the coordinatively unsaturated copper site (Cu_CUS) was energetically preferred on the Cu₂O(111) surface. In addition, the electronic structure information for several typical configurations were explored to explain the detailed interaction mechanism of adsorbed systems.