DYNAMICAL DIFFRACTION IN QUASI-CRYSTALS

Despite the absence of periodic order, standard Darwin diffraction profiles have been produced by an exact numerical calculation of x-ray reflectivity from a model quasicrystalline layered structure. A simple real-space construction with the quasiperiodic charge distribution projected in a reduced-zone scheme is used to explain the effects of absorption on the Darwin curve. This picture also helps to explain quasicrystal standing-wave yields, the possibility of anomalous transmission, and the meaning of inversion symmetry in such aperiodic structures. © 1995 The American Physical Society.