THE NATURE OF METAL-METAL BONDING AT BIMETALLIC INTERFACES

The nature of the electronic and physical properties of ultrathin metal films on several transition metal substrates have been studied using X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD). The results indicate that the admetal monolayers have electron densities that vary significantly from those of the corresponding pure metals. Correlations are found among the electronic perturbations of the monolayer films, the admetal-substrate cohesive bond strength and the chemisorption properties of the monolayer films toward CO. A simple model is described to explain the direction and magnitude of the electronic perturbations.