Investigation of the adsorption and diffusion interaction of atomic hydrogen with low-index surfaces of crystal aluminum nanoplates

By the method of density functional in the local density and generalized gradient approximation, the dependences of the potential energy of interaction of atomic hydrogen with low-index surfaces of aluminum nanoplates have been calculated. The spatial configurations of hydrogen atoms and surface layers of the plate corresponding to the stable structures formed by adsorption and diffusion have been determined. It has been shown that atomic hydrogen is adsorbed irreversibly on the Al surface, releasing energy of 2.8-3.1 eV whose value is determined by the atomic structure of the surface. On the atomic planes (100) and (110), the bridge form of chemisorption has the minimum energy. For the (111) surface, the energy-stable state is realized in the threefold coordinated position of the hydrogen atom. Diffusion of hydrogen is an activated process in which energy of 0.5-0.8 eV is absorbed depending on the atomic structure of the plate. Atomic hydrogen moves through interatomic voids sequentially occupying octa- and tetrahedral positions. It has been established that the transient state between stable Oh and Td positions in the bulk of the plate is the geometrical configuration of the hydrogen atom having third-order symmetry. © 2011 Springer Science+Business Media, Inc.