A dose dependence study of O(2) adsorbed on large Ar clusters

An investigation of the behavior of O(2) molecules in and on O(2)-doped large (N approximately 8000) Ar host clusters has been performed by means of core and valence photoelectron spectroscopy. Data from pure O(2) and Ar clusters, as well as from O(2)-doped Ar clusters, are presented. The experimental data together with calculations of the binding energy shifts of oxygen molecular ions in and on the surface of a large host Ar cluster show that the diffusion behavior has a strong dependence on the doping pressure. We conclude that the oxygen molecules in the doped Ar host do not partake in band formation, since there is clear vibrational resolution in the spectral features stemming from screened O(2) (+) ions. This implies that valence photoelectron spectroscopy can be used to determine the geometrical structure of this and certain, similar, cluster systems.