X-RAY REFLECTIVITY FINE-STRUCTURE FROM HOMOGENEOUS MATERIALS IN THE HARD-ENERGY RANGE

To a good approximation, the x-ray reflectivity fine structure from homogeneous materials was found to be, in the hard-energy range, a linear superposition of the fine structures of the real and imaginary parts of the refractive index. As a consequence, a simple formula for the extraction of the absorption fine structure (EXAFS) from the reflectivity data is given. For a certain glancing angle, the Kramers-Kronig transform of the reflectivity fine structure is, to a constant factor, approximately equal to EXAFS. The magnitudes of the Fourier transform of the reflectivity fine structure and of EXAFS have for all glancing angles approximately the same shape.