Vacuum ultraviolet reflectivity of small gold clusters

We report on the reflectivity spectra of continuous (d=1000 A{}) and discontinuous (d=12, 25, 35, and 50 A{}) gold films evaporated onto fused quartz substrates, measured in the photon energy range 15--35 eV using synchrotron radiation. The spectra of very thin films are attenuated and shifted predominantly towards higher energies relative to the bulk gold one. The shifts are explained in terms of a modification of the Au band structure induced by the contraction of the fcc nearest-neighbor distance.