Determination of Local Structure of Molecules Adsorbed on Solid Surfaces by XANES

Abstract
A method of inverse problem solution in the many-centre shape resonance theory is applied to study adsorption states of molecules on solid surfaces. The main idea is to the effect that positions and widths of maxima in XANES related to quasi-stationary one-electron states (shape resonances) depend considerably on local geometry of molecules. The oxygen K spectra of physisorbed and chemisorbed O₂ on Cu(100) were investigated. An adsorptive complex was simulated by clusters containing up to eight atoms. It was found that the chemisorbed molecule location is on the Cu atom, the Cu-O distance is 2.01 Å and the changed O-O distance is 1.38 Å.