Showing papers by "David A. King published in 1984"

Chapter 1 Kinetics of Adsorption, Desorption and Diffusion at Metal Surfaces

Abstract: Publisher Summary This chapter discusses the kinetics of adsorption, desorption, and diffusion at metal surfaces and the gas–solid surface interaction potential. Two schematic combined potential energy wells for the interaction of a gaseous species with a surface are presented diagrammatically illustrating the importance of the crossover point of the chemisorption and physisorption wells for adsorption and desorption kinetics. In the first case, adsorption is activated; in the second, it is nonactivated. The potential interaction between H 2 and a magnesium surface, which substantiate the presence of two minima, is calculated. The order–disorder phenomena in adsorbed layers are discussed. If there were no lateral interactions between adsorbed species, equilibrium adsorption would occur with the random occupation of preferred site configurations. However, since the advent of low-energy electron diffraction (LEED) as a tool for determining the long-range structural order of a surface it has been known that disorder in thermally equilibrated chemisorbed overlayers is the exception rather than the rule, even at relatively low surface coverages.