The potential surfaces and electronic structures of adsorption states of O on the (100) faces of various Ag clusters were calculated ty the EHMO method. The potential surfaces show that the O mols. are located in the troughs of W110V direction at a height of 0.9 ?for the mol. state adsorption on Ag(110) and the O atoms ar located in the troughs between the 2 first layers of Ag atoms at a height of 0.6 ?for atomic state adsorption. The calculated electronic structure indicates that O adsorption on Ag causes some electron densities to flow from Ag into 2p AOs (AOs) and sg* antibonding MOs of O and while simultaneously part of the electron d. flows backward from the bonding pu and 3sg MOs into the Ag 5p AOs. The resulting adsorbed species are O-1.5 and O2-1.318. The dependence of mol. state adsorption properties of O on the surface structure of Ag is discussed in terms of calculated and experimental results.

Key words: OXYGEN, SILVER, QUANTUM CHEMISTRY, CLUSTER COMPOUND, ELECTRONIC STRUCTURE, BONDING, POTENTIAL ENERGY SURFACE, THEORETICAL ANALYSIS, SURFACES ADSORPTION, ADSORPTION STATE