ADSORPTION AND SURFACE-REACTION OF SO2 ON CU(100) STUDIED BY S-K-EDGEXAFS AND STM

Adsorption and reaction of SO2 on Cu(100) at roam temperature has been studied by means of S K-edge XAFS, AES, LEED, XPS and STM. It has bee n revealed that there are atomic S and SO3 with the stoichiometric rat io of 1:2 on the surface. This indicates that a disproportionation rea ction of 3SO(2)(a)-->S(a)+2SO(3)(a) occurs at room temperature. The at omic S locates in the fourfold hollow sire. SO3 adsorbs with its trigo nal pyramid upright on the surface. The (2x2) and c(4x6) domains were observed by STM. The former contains only one SO3 species in the unit cell without atomic S, while the latter involves one SO3 and two atomi c S. This implies the occurrence of drastic migration of resultant pro ducts.