Bonding of atomic oxygen to Cu(100) and Ag(100) surfaces: a study of the nature of the interaction

Abstract

The nature of the chemisorption bond between atomic oxygen and the Cu(100) and Ag(100) surfaces has been studied through the ab initio molecular orbital cluster model approach. Cluster models of increasing size, as Cu 5, Cu 25, Cu 41 or Ag 5, Ag 25 and Ag 41 have been used to test the influence of cluster size on the physics of the interaction. Use of an orbital projection technique and of the dipole moment curves permits to establish that the bonding mechanism on both surfaces is the same and can be described as a largely ionic bond. The extent of the direct participation of the metal d-electrons has been studied through the Constrained Space Orbital Variation method. This participation is roughly 20% of the total interaction energy. The picture of the chemisorption bond does not change with the size of the cluster model.