Thermal Diffuse Scattering in X-Ray Diffraction by Aluminium

Abstract

The purpose of this work is to investigate the diffuse streak patterns in X-ray diffraction quantitatively by numerical calculation of the three dimensional intensity distribution of the thermal diffuse scattering in the reciprocal space of aluminium at 293 K. The contributions of the harmonic first- and second-order thermal diffuse scatterings and the lowest-order anharmonic scattering were evaluated individually. The calculation was carried out by the use of the inverse dynamical matrices for up to 400 samples of wave vectors within the first Brillouin zone. The data of the interatomic force constants were taken from Gilat and Nicklow's article (Phys. Rev. 143 (1966) 487), in which the axially symmetric Born-von Karman force constant model including nearest neighbours from the first to the eighth was used. The results of our calculation agree with photographic observation of the diffuse streaks well.