Photoemission Observations of Resonant d Levels and d -Band Formation for Very Thin Overlayers of Cu and Pd on Ag

Photoemission studies of very thin overlayers of Cu and Pd on Ag substrates show resonant bound d states with half-widths Γ0.5, and 0.8 eV centered at 2.5 and 1.2 eV below the Fermi energy EF, respectively, for depositions {} 2 average monolayers, and show the formation of bulk band structure for deposition {} 4 monolayers. The d-resonance position for Pd on Ag (1.2 eV below EF) is markedly different from that of dilute Pd in AgPd alloys (2 eV below EF), while the level widths are comparaable.