Abstract

The energy dependence of the integrated intensities Ih() and Ih() and of their ratio rh(), around an absorption edge, are greatly affected by thermal vibrations of atoms. This has been experimentally shown by the present energy-dispersive diffractometry for a mosaic crystal of CuI, for which thermal vibrations are especially large even at room temperature. The temperature factor values BCu = 3.3 plus or minus 0.1 and B1 = 2.0 plus or minus 0.1 A2 have been determined in the following way: the fCu() curve has been determined from the absorption curve, and therefrom the f'Cu() curve has been calculated by the dispersion relation. By the use of these curves, the intensity curves I555() and I() were obtained, and then the temperature factors were determined by finding the best fit between the above I() curves and the observed one. Also, the experimental fine structure of the Friedel ratio r5() is shown as a function of energy and compared with the calculated values.