Determination of Long-Range Interaction Energies from the Scattering of X Rays by Disordered Alloys

A method for determining the interparticle interaction energies in a disordered alloy from the corrected diffuse scattering intensities of x rays is presented. This method, which is based on the ordering theories, is applied to the problem of obtaining the first seven pair-interaction ratios in ${\mathrm{Cu}}_3$ Au from the experimental data of Moss. Strong evidence for the presence of long-range pair interactions originating from the indirect screening interaction between ions is obtained for ${\mathrm{Cu}}_3$ Au, indicating the existence of a reasonably sharp Fermi surface in this alloy, at temperatures of the order of 700 °K.