REACTIVITY AND STRUCTURE OF CF3I ON RU(001)

A variety of surface-sensitive techniques are used to elucidate the re action pathways, as well as adsorbate structures, associated with ther mal activation of CF3I following adsorption on Ru(001) at 100 K. XPS s hows that the C-I bond of CF3I dissociates below 200 K to form CF3(ad) and I(ad); the subsequent reactions of CF3 are best viewed as being r egulated by the availability of surface sites. CF3(ad) dissociates to CF2(ad) below 200 K. Further CF3 dissociation, some of which is activa ted by H(ad), occurs between 200 and 400 K until all available sites a re filled. Desorption of the remaining CF3, peaking at 705 K, once aga in opens surface sites for decomposition. This is followed by recombin ation of the products to form CF3(g). No evidence for CF(ad) is ever o bserved. Hydrogen coadsorption studies explain interesting features as sociated with fluorine evolution. HREELS and ESDIAD results indicate t hat CF3 adopts a tilted configuration on Ru(001).