Adsorption of mercury on gold and silver surfaces

In order to study the adsorption mechanism of Hg on Au and Ag substrates, t hin film Au(111) and Ag(111) substrates were exposed to gaseous metallic me rcury, while the mercury concentration, substrate temperature, and exposure length were varied. The resulting changes in the surface morphology of the substrates were studied with scanning tunneling microscopy (STM). The amou nt of adsorbed Hg required to cause saturation, i.e. a decrease in the adso rption rate was found to be dependent on the mercury concentration and subs trate temperature. The observations lead to the conclusion that the adsorpt ion includes place exchange processes and concerted adsorption of more than one Hg atom in one process. The results show that the collection efficienc y of single-crystalline surfaces is a function of both mercury concentratio n and temperature. Therefore, results from measurements performed at differ ent conditions using single-crystalline surfaces may not be comparable.