Semiempirical band calculation of Pd-adsorbed SnO2 surface

The electronic structure of a Pd-adsorbed SnO2 (001) surface is calculated using a semiempirical tight-binding method. When a Pd atom bridges two oxyg en atoms on the SnO2 (001) surface, bonding and antibonding states arising from the admixture of Pd 4d and O 2p orbitals are formed around -15 eV and -8.35 eV. The energy levels of these bonding and antibonding states are ove rlapped with those of the valence and conduction bands. Nonbonding states o riginating from Pd 4d are calculated to be -9.2 eV and are located near the bottom of the conduction band of SnO2. The Fermi level of -8.37 eV is pinn ed at the nonbonding states with a large state density. When two Pd atoms a re bound to two oxygen atoms on SnO2 (001), Pd-related states exhibit a ban dlike character in spite of less than one monolayer coverage.