Local Density of States (LDOS) of Model Clusters for Surface Electronic States : Ag (111)

Theoretical calculations using the DV-Xα-MO method have been performed for various clurters (3-10 atoms) to investigate the electronic structure of Ag (111) surface. The total density of states (TDOS) curves for the clusters are not in agreement with the experimental ARPE spectra because of the large contribution of edge atoms. To minimize the edge effects we have calculated the local DOS (LDOS) for a surface central atom surrounded by all of their nearest-neighbour atoms and have found that the LDOS curves are in good agreement with experimental spectra. Moreover it was found that the LDOS curve composed of the orbitals with total symmetry is in very good agreement with normal emission APRE spectra, indicating that the LOOS method is compatible with the symmetry selection rules.