Effects of vacancy and step on dissociative dynamics of H2 on Pd (1 1 1) surfaces

Based on our recently developed reactive force field, we studied dissociative dynamics of H2 molecule on Pd (1 1 1) surface with vacancy and step. The results show that vacancy results in a little higher probability than perfect surface. Further analysis shows that vacancy can hinder the diffusion of H2 molecule in the dissociation dynamics. Moreover, it is found that the probability of step is higher than that of perfect surface but it is insensitive to the height of step. The roles played by the direct dissociation at high energy and bond counting mechanism at low energy are discussed.