Atomic background in $4p$ elements

In the 4p elements from G-a to Kr the atomic background is determined by removing the ,structural component from Ample EXAFS spectra of chalcogenid¢ glasses, solutions and vapors. The baclq~und comprises sharp features due to ls3d and ls3p multielecVon photoexcitations, such as found in the atomic absorption spectrum of gaseous krypton. A spline background, generated by the FEFF "autobk" routine accounts properly for the long-wavelength components, but misses the sharp details of the amplitude of-l% of the K edge jump. This is sufficient to spoil the ~ parameters in EXAFS analysis in some cases