TRANSITION-STATES FOR NO AND CO DISSOCIATION ON CU (100) AND CU (111)SURFACES

The transition states for dissociation of NO and CO have been located and optimized for several reaction paths on cluster models of the copp er (100) and (111) surfaces using density functional theory. Classical transition state theory was then used to calculate the rates of disso ciation and recombination. The partition function of the transition st ate is substantially smaller than that of the reactant state, correspo nding to pre-exponentials for dissociation in the range 10(10)-10(12) s-1. The dissociation barrier for NO is significantly lower than that for CO. In addition, the less densely packed Cu(100) surface is more r eactive towards dissociation than the close-packed Cu (111) surface.