A more precise expression for the angular deviation from the Bragg law and the angularrange of X-ray diffracted by perfect crystal are derived. The critical angle of the total re-flection of X-ray from the surface of ...A more precise expression for the angular deviation from the Bragg law and the angularrange of X-ray diffracted by perfect crystal are derived. The critical angle of the total re-flection of X-ray from the surface of crystal is obtained naturally by the new expressions,which well coincides with that deduced in optics in consideration of the refraction. Twopeaks appear on the rocking curve when X-rays shoot at the surface at a small glancing angleand simultaneously on the side of crystal although the double-crystal is in (n, -n) setting,which is called the "edge effect". The angle between these two peaks on the rocking curvecan be used to measure the number of electrons in an unit cell of crystal.展开更多
This structural study of quasicrystals is based on extremely dense icosahedral unit cells that are systematically and consistently measured for the first time. The structure and pattern indexation are 3-dimensional. A...This structural study of quasicrystals is based on extremely dense icosahedral unit cells that are systematically and consistently measured for the first time. The structure and pattern indexation are 3-dimensional. A formula is given for scattering from atoms in hierarchic arrangement and geometric series. The Quasi-Bragg law is a new law in physics, with possible applications beyond crystallography. The structure is compared with previous, unsuccessful, and contradictory, attempts at analysis.展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘A more precise expression for the angular deviation from the Bragg law and the angularrange of X-ray diffracted by perfect crystal are derived. The critical angle of the total re-flection of X-ray from the surface of crystal is obtained naturally by the new expressions,which well coincides with that deduced in optics in consideration of the refraction. Twopeaks appear on the rocking curve when X-rays shoot at the surface at a small glancing angleand simultaneously on the side of crystal although the double-crystal is in (n, -n) setting,which is called the "edge effect". The angle between these two peaks on the rocking curvecan be used to measure the number of electrons in an unit cell of crystal.
文摘This structural study of quasicrystals is based on extremely dense icosahedral unit cells that are systematically and consistently measured for the first time. The structure and pattern indexation are 3-dimensional. A formula is given for scattering from atoms in hierarchic arrangement and geometric series. The Quasi-Bragg law is a new law in physics, with possible applications beyond crystallography. The structure is compared with previous, unsuccessful, and contradictory, attempts at analysis.
