RESUMO
We report ab initio calculations of the x-ray absorption cross section for the near edge x-ray absorption fine structure of C2H6, and C2H4, and C2H2 at the C K-edge, based on a full multiple scattering formalism. The angular dependence of the electric dipole transition in the calculations as well as the angular dependent experiments for the oriented molecules give a good opportunity to compare both. The resonance can be assigned to a sigma(*) shape resonance. The multiple scattering formalism and the experiment agree well and thereby support the existence of such features in the spectra.
RESUMO
The magnetic moments in Ni/Pt multilayers are thoroughly studied by combining experimental and ab initio theoretical techniques. SQUID magnetometry probes the samples' magnetizations. X-ray magnetic circular dichroism separates the contribution of Ni and Pt and provides a layer-resolved magnetic moment profile for the whole system. The results are compared to band-structure calculations. Induced Pt magnetic moments localized mostly at the interface are revealed. No magnetically "dead" Ni layers are found. The magnetization per Ni volume is slightly enhanced compared to bulk NiPt alloys.