Structure determination of ethylene adsorbed on Ag(100) surface by multiple-scattering cluster method

The carbon K-shell near edge X-ray absorption fine structure (NEXAFS) spectra of gas-phase ethylene molecules and ethylene adsorbed on Ag(100) have been calculated by the multiple scattering cluster method (MSC) for the first time. The calculated results show that carbon-hydrogen scattering resonances exist in the carbon K-shell NEXAFS spectra for both gas-phase ethylene molecules and ethylene adsorbed on the metal surface. By a comparison between the theoretical results and experimental spectra, we have found that ethylene molecules are adsorbed on the Ag(100) surface taking a four-fold hollow-site with the direction of the CC bond parallel to the 001] or 010] direction, the bond lengths of CC and AgC are equal to 1.40 ± 0.02 and 1.96 ± 0.03 Å, respectively. These results can be compared with that of the C₂H₄-Cu(100) system.