Stability of Coincidence Lattices for Chemisorbed Structures

Abstract

The author previously reported a variety of coincidence lattices for oxygen chemisorbed on single‐crystal faces of platinum by low‐energy electron diffraction. The purpose of the present work is to show that theoretical calculations confirm the stability of such structures. For the case of two one‐dimensional lattices it is shown that both a coulomb and a cosine interaction potential do not lead to any significant lowering of the energy for coincidence lattices. However, a variety of other potentials do favor the formation of coincidence lattices when the lattice parameters are in the ratio of small whole numbers. Since the Coulomb interaction leads to a potential which is virtually indistinguishable from the cosine potential for cases of interest, it is concluded that deviations from the cosine potential favor the formation of coincidence lattices. It is further concluded that in real cases such deviations exist.