Fig. 1.

Dependence of the effective scattering factors and of bromine on the energy of the incident X-ray beam. The scattering factor taken from Henke et al. and Brennan and Cowan [21, 22] is plotted against the energy of the incident beam. The energy of the edge is marked by a dashed line. The breadth of the energy distribution of the primary beam is approximated by a Gaussian and given by a dash-dotted line. The finite width of the primary beam imposes no problem unless the experiment is done in the immediate neighborhood of the edge. Then the effective scattering factors and result from a convolution of the energy spread of the primary beam with or , respectively [25, 27]