EFFECT OF SPATIAL ANISOTROPY OF UNIAXIAL CRYSTALS ON X-RAY REFLECTION: ORIENTATION DEPENDENCE OF K REFLECTION SPECTRA OF HEXAGONAL BN AND CdS CRYSTALS

摘要

The BK and NK reflection spectra of a hexagonal BN crystal and the SK reflection spectra of a hexagonal CdS crystal were studied. The results of the investigation indicated that there was an orientation dependence of the fine structure of the reflection spectra of uniaxial crystals near the K resonances, i.e., in the region when the wave function of the initial state of the transition was spherically symmetric. In hexagonal BN crystals, these effects were due to the strong anisotropy of chemical bonding of boron and nitrogen atoms in the plane layer and along the normal to it. For hexagonal CdS crystal, the dependence revealed was likely to be due to the dominant role of the resonance effects in the regions between distant coordination spheres. A planar anisotropy of the surface was revealed.