Progress in powder and surface X-ray diffraction crystallography

Abstract

One of the most important scientific achievements of the XX century has been without any doubt the discovery of X-ray diffraction by crystalline matter and the subsequent use of this process to determine the crystal structures of the materials. This field matured at the end of the century with the almost automated solution of the crystal structures of small compounds, allowing various new applications of X-ray diffraction methods to emerge. Among the most relevant ones for Materials Sciences one may mention the solution of crystal structures from X-ray powder diffraction intensity data or the determination of atomic arrangements in the surfaces of substrates and, eventually, of the corresponding depositions. Since these advances are closely related to a recent reinterpretation of the traditional direct methods of solving crystal structures, a short introduction to them will be given first. Then we deal with the modification of such methods to cope with the particularities of these two applications and, finally, some examples will be described.