A photoelectron study of palladium,nickel, and copper clusters on carbon surfaces

Ultraviolet photoelectron spectra show that even at the threshold of detectability, Pd, Ni, and Cu atoms deposited on the basal plane of cleaved graphite nucleate into clusters sufficiently large to exhibit valence band and core binding energies characteristics of bulk metals. However at very low coverage of these metals on amorphous carbon, the spectra show that the valence d-bands have decreased widths and larger binding energies than the bulk metals. Core binding energies show a similar increase at very low coverage. These effects occur because at low coverage on amorphous carbon these metals are present as isolated adatoms.