Analysis Of Crystal Structure And Diffuse X-ray Scattering From SrF₂

In this paper, using X-ray CuKα radiation measured thermal diffuse scattering intensity on powder Sr F2. The crystal structure parameters were refined and the temperature factor B was obtained using RIETAN-2000 program. Using these parameters calculated the diffuse scattering intensity and an oscillatory scheme of the diffuse scattering intensity was obtained.First, the crystal structure of SrF2 was tested by X-ray diffraction(XRD) at room temperature(25 ℃). Refined the crystal structure parameters and obtained the temperature factor B using Rietvled method which was carried out in the program RIETAN-2000. Furthermore, the XRD results were analyzed with Maximum Entropy Method(MEM) and the electron density distributions were shown clearly in the form of equal pitch contour, which realized the visualization of the distribution of electron density.Second, the background intensity function of SrF2 was expanded according to the theoretical equation of thermal diffuse scattering intensity. The diffuse scattering intensity was calculated using the parameters that obtained by the refinement. And the value of correlation effects μ among thermal displacements of atoms was deduced. The oscillatory scheme of the diffuse scattering intensity which deduced with the value of μ was consistent with the patterns of experimental results. The result showed that the contribution of the oscillatory scheme of NaCl would be from the correlation effects among the thermal displacements third and fourth nearest neighboring atoms.