Theory and Applications of X-ray Standing Waves in Real Crystals

Theoretical aspects of x-ray standing wave method for investigation of the real structure of crystals are considered in this review paper. Starting from the general approach of the secondary radiation yield from deformed crystals this theory is applied to different concreat cases. Various models of deformed crystals like: bicrystal model, multilayer model, crystals with extended deformation field are considered in detailes. Peculiarities of x-ray standing wave behavior in different scattering geometries (Bragg, Laue) are analysed in detailes. New possibilities to solve the phase problem with x-ray standing wave method are discussed in the review. General theoretical approaches are illustrated with a big number of experimental results.Comment: 101 pages, 43 figures, 3 table

Atomic structure and lattice dynamics of Ni and Mg hydroxides

Lattice dynamics of nickel hydroxide, β-Ni(OH)2, electrode material for current batteries, has been investigated by incoherent inelastic neutron scattering. Results are discussed through comparison with the isostructural and well studied model compound, Mg(OH)2. The zone-center phonon spectra calculated in the frame of the density functional theory showed the important role of the spin–spin interactions in nickel hydroxide. Analysis of the calculated force constant matrix provided some insight into peculiarities of interatomic interactions in these layered compounds. A similar theoretical approach is applied to the investigation of the atomic structure and lattice dynamics of the β-NiOOH phase