Bayes-Turchin analysis of x-ray absorption data above the Fe L2,3-edges

Extended x-ray absorption fine structure EXAFS data and magnetic EXAFS MEXAFS data were measured at two temperatures 180 and 296 K in the energy region of the overlapping L-edges of bcc Fe grown on a V 110 crystal surface. In combination with a Bayes-Turchin data analysis procedure these measurements enable the exploration of local crystallographic and magnetic structures. The analysis determined the atomiclike background together with the EXAFS parameters which consisted of ten shell radii, the Debye-Waller parameters, separated into structural and vibrational components, and the third cumulant of the first scattering path. The vibrational components for 97 different scattering paths were determined by a two parameter forcefield model using a priori values adjusted to Born-von Karman parameters of inelastic neutron scattering data. The investigations of the system Fe/V 110 demonstrate that the simultaneous fitting of atomic background parameters and EXAFS parameters can be performed reliably. Using the L2and L3-components extracted from the EXAFS analysis and the rigid-band model, the MEXAFS oscillations can only be described when the sign of the exchange energy is changed compared to the predictions of the Hedin Lundquist exchange and correlation functional.