Dynamics of adsorption on clean and adsorbate-modified transition metal surfaces. (Progress report, 1989--1991)

摘要

Research is being carried out on both nondissociative and dissociative adsorption of gases on transition metal surfaces, with emphasis on alkanes. Particular attention is be placed on understanding the effects of adsorbed species on adsorption probabilities and on clarifying the role of energy exchange processes at the surface in both dissociative and nondissociative adsorption. Molecular beam methods are coupled with methods of surface science to gain the greatest control of the variables of the problem, including the incident kinetic energy, vibrational energy and angle of incidence of the incoming molecules. The dynamics of both direct and precursor-influenced dissociative adsorption routes are examined. Surface intermediates formed by activated adsorption are identified by vibrational spectroscopy and temperature programmed reaction. Emphasis is on comparative studies of low molecular weight alkanes in order to understand the origin of the differences in their reactivities on different metals.