Structural studies of alkali metal adsorption and coadsorption on metal surfaces

The study of the adsorption and the coadsorption of alkali metals on single-crystal metal surfaces is a very active sub-field of surface science, partly because of the importance of technological applications (promotion of catalytic reactions, enhanced oxidation, increases in electron emission rates), but also because of the fundamental interest in how these ''simple'' adsorbates modify the surface. In the past few years there has been a marked increase in the number of structural studies of alkali adsorption and coadsorption systems, motivated in part by developments in theoretical models of adsorption. This article reviews recent studies of alkali adsorption and coadsorption using specifically structural techniques, with the intention of highlighting recent developments, providing a useful reference base to the community, and drawing attention to some unifying concepts.