DISSOCIATIVE CHEMISORPTION OF HYDROGEN MOLECULES ON THE SI(111) (1X1)SURFACE - 1ST-PRINCIPLES CALCULATIONS

The dissociative chemisorption for hydrogen molecules on the Si(111) ( 1 x 1) surface has been studied using a first-principles method. A dir ect dissociative chemisorption process was found. The direct dissociat ion happens at the saddle point of the potential energy surface for hy drogen atoms moving on the Si(111) (1 x 1) surface. A two-dimensional potential energy surface was presented to show the direct dissociation . Different orientations of H-2 interacting with the surface were also investigated. The calculations showed that H-2 always favours having the molecular axis parallel to the surface.