Kinetic study of the formation of a surface-confined Cu sub 50 Pt sub 50 alloy

Using Auger electron spectroscopy we demonstrate the determination of the energy barrier for the formation of a surface-confined Cu sub 50 Pt sub 50 (111) bilayer alloy. Starting with one monolayer of Cu on Pt(111) concentration changes are determined as a function of annealing temperature up to 600 K and annealing time. Comparison of the experimental data with Monte Carlo simulations give the best result for the assumption of a Cu sub 50 Pt sub 50 surface alloy yielding an energy barrier for interlayer mixing of 1.11plus/minus0.12 eV/atom. Concomitant valence band photoemission spectra also indicate the alloy formation.