New opportunities in the soft X-ray absorption to characterize the adsorbate bonding

摘要: One of the important applications XAS in soft X-ray regime is ability to measure EXAFS light elements, like carbon, nitrogen, etc. up sulfur and chlorine. These adsorbed on metal surfaces, are most constituents for investigation gas-metal interactions. decade ago, surface world was harmonic, nearest neighbor distances were determined within harmonic approximation, R did not change with temperature, coordination number N from measurements at a single temperature. Recently, SEXAFS data taken as function T various angles incidence. This advance, combination multiple scattering analysis full simulation computer codes, allows routinely determine pair distribution third moment. We relate general terms Einstein local static disorder thermal expansion ionic versus covalent bonding, shape effective potentials adsorbate induced reconstruction. Furthermore, these low Z systems ideal candidates detect unambiguously photoelectron backscattering by interstitial charge densities (AXAFS).