Photoelectron spectrum from atomic wave function

The EXAFS function, ffk). is extracted from the X-ray absorption spectrum in Fig. 6.11 by removing first the approximately parabolic background and next the step, i.e. the spectrum of the free atom in Fig. 6.11. As in any scattering experiment, it is customary to express the signal as a function of the wave number, k, rather than of energy. The relationship between k and the kinetic energy of the photoelectron is... 

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