Structure of disordered matter and its measure though diffraction

The understanding of the properties of glasses or of liquids requires the knowledge of the partial structure factors (PSF) that describe the spatial distribution of an atomic species around another one. Combining neutron diffraction techniques (particularly the one with isotopic substitution: NDIS) with the anomalous X-ray scattering technique (AXS) allows us to get a better contrast in terms of scattering lengths but implies to carry out a thorough data analysis because the handling of systematic errors is different for the 2 techniques. This method has previously been validated on atoms whose electron distributions are quasi-spherical. In the case of glasses with important covalent bonds, the use of this method is made easier when it deals with high atomic number elements. This paper describes the method from how PSF parameters are inferred from differential cross sections, to the application to AXS and to NDIS. (A.C.)