Abstract: We have calculated the sulphur 1s near edge X-roy absorption fine structure (NEX-AFS) spectra of SO2 adsorbed on Pd( 111 ) in terms of the multiple-scattering Cluster(MSC) method. The origin of the resonances in the NEXAFS spectra has been re-xealed. By the MSC calculation and a (DV)-Xα study we have for the first time iden-tiffed two weak features existing in S K-edge NEXAFS of SO2/Pd(111) system, whichare attributed to the interaction between the adsorbate and the substrate. Moreover,MSC calculation together with the reliability factor (R-.factor) analysis are employedto determine the local adsorption structures. These results are broadly in agreementwith those of Fourier-transform analysis of the surface extended X-ray absorption finestructure (SEXAFS).

Key words: multiple-scattering cltster. near edge X-ray absorption fine structure, SO2 /Pd(111). D V-Xα method