Atomic background in 4p elements

In the 4p elements from Ga to Kr the atomic background is determined by rem oving the structural component From simple EXAFS spectra of chalcogenide gl asses, solutions and vapors. The background comprises sharp features due to 1s3d and 1s3p multielectron photoexcitations, such as found in the atomic absorption spectrum of gaseous krypton. A spline background, generated by t he FEFF "autobk" routine accounts properly for the long-wavelength componen ts, but misses the sharp details of the amplitude of similar to 1% of the K edge jump. This is sufficient to spoil the structural parameters in EXAFS analysis in some cases.