High-resolution atomic distribution functions of disordered materials by high-energy X-ray diffraction

The atomic-scale structure of materials with different degrees of structural disorder has been investigated by high-energy (E⩾60 keV) X-ray diffraction. Good quality structure functions extended to wave vectors of magnitude Q⩾40 Å−1 have been obtained even in case of materials composed of weakly scattering, light atomic species. The corresponding high-resolution atomic distribution functions allowed fine structural features differing in as little as (0.14 Å) to be resolved. In particular, the distinct Ga–As (∼2.43 Å) and In–As (2.61 Å) bonds in In–Ga–As alloys have been differentiated. The atomic-scale structure of `restackedʹ WS2 has been determined and the presence of three distinct W–W distances occurring at 2.77, 3.27 and 3.85 Å established. Finally, Si–O (∼1.61 Å), Al–O (∼1.75 Å) and Ca–O (∼2.34 Å) bonds in calcium aluminosilicate glasses have been differentiated and the characteristics of the respective co-ordination polyhedra revealed.