THE ADSORPTION OF AG ON CO, O AND H COVERED W(110) .2. METALLICITY

Monolayers of Ag adsorbed on O/W(110), CO/W(110) and H/W(110) give rise to work functions nearly identical to those of thick Ag deposits on clean W(110) and also show bulk and surface plasmon losses seen only for 3 or more Ag monolayers on clean W(110). UPS spectra show a 4d peak closer in energy to that of Ag multilayers on clean W than for a single layer. There are only very small (approximately 0.1 eV) core level shifts relative to Ag1/W(110) or Ag3/W(110). These facts indicate that metal atoms capable of forming partially filled s-bands show metallicity even as monolayers, and that partial decoupling from the W substrate by intervening chemisorbates makes the properties of such monolayers closer to those of the bulk overlayer metal than when a single layer is in good physical and electronic contact with the substrate.