H2 dissociative adsorption on Pd(111)

The dissociative adsorption of hydrogen molecules on the (111) surface of palladium is studied by total-energy calculations using the density-functional theory within the framework of the generalized gradient approximation. A variety of dissociation pathways is investigated. Both activated and nonactivated pathways are found. We carry out a detailed analysis of the electronic structure along the different pathways to understand the microscopic mechanism of bond breaking and bond formation. This analysis allows us to account for the energetic ordering of the transition states. Precursor states are also identified for the system considered here.