The coadsorption of K and Cl on Ag(100): Electronic, kinetic and thermodynamic surface modification by promotion

摘要: The coadsorption of potassium with chlorine substantially alters the nature latter in chemisorbed phase. electronic levels CI are shifted to higher binding energy respect substrate (by ~ 2,5 eV case 2p level) due electrostatic effects proximate ions. In reverse sequence, shifts K opposite direction, but by a lesser magnitude. presence also has substantial on energetics interaction silver surface. It induces AgCl crystallite formation at surface; such crystallites only formed absence much lower temperatures as heating more than 250 results their dissolution into bulk crystal. these surface thermally stabilised and do not begin dissolve lattice until 400 K. At 450 it appears that coadsorbed K/Cl layer phase separates form KCl crystallites, While further 700 desorption very narrow peak (~ 20 FWHM). If multilayers have been adsorbed 310 dissolved heating, resegregates back 550 100 undoped surface) possibly endothermic heat segregation free case. Above all remaining after evaporation is lost gas