On the Method of Constructing the Radial Distribution Function in the Structure of Amorphous Materials on the Basis of D
- PDF / 469,370 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 59 Downloads / 192 Views
CTURE OF INORGANIC COMPOUNDS
On the Method of Constructing the Radial Distribution Function in the Structure of Amorphous Materials on the Basis of Diffraction Data O. I. Vasina, A. K. Kuliginb, V. V. Novikovab, and A. S. Avilovb,* a Krasnodar b
Higher Military School Named after General of Army S.M. Shtemenko, Krasnodar, 350063 Russia Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,” Russian Academy of Sciences, Moscow, 119333 Russia *e-mail: [email protected] Received April 17, 2019; revised April 22, 2019; accepted May 6, 2019
Abstract—The method of constructing the radial distribution function, proposed by the authors previously, has been developed. The method includes calculation of the normalization factor and subtraction of the background caused by incoherent scattering in the amorphous material. Software is developed based on the proposed algorithms. The reported technique for processing the angular dependence of the scattered radiation intensity is approved on well-studied amorphous germanium and tungsten trioxide WO3. This technique makes it possible to perform a reliable (accurate to few percent) normalization of intensity and determine the coordination number n1 for an arbitrarily specified density of material, independent of the shape of the first coordination peak. In sum, a universal software tool has been elaborated, which makes it possible to investigate the structure of amorphous and polycrystalline inorganic materials by constructing the radial distribution functions, using diffraction of radiation of any type in these materials. All calculations are performed in the automatic mode. DOI: 10.1134/S1063774519050249
INTRODUCTION The atomic structure of material is its fundamental characteristic. In contrast to crystalline state structure of amorphous materials (the so-called glasses) is described by “short-range order”, which leads to the occurrence of wide “halo”-type peaks in diffraction patterns. Conventionally, structural analysis is performed as follows: diffraction patterns, which is characterized by the presence of “long-range order”, the atomic are obtained, the structural factor is determined, and the radial distribution functions (RDFs) are constructed; the latter are then used to build a structural model by either selecting pair correlation functions (PCFs) or directly. In principle, one can derive a distribution of distances between atomic pairs in any condensed material from a diffraction pattern. This distribution is mapped as a sequence of peaks, beginning with the shortest distances between atomic pairs in the material and ending with the longest ones. The areas under the peaks in PCF plots are proportional to the number of atomic pairs located at the corresponding distances, and the peak widths are proportional to the meansquare deviation σ2 of these distances.
Analysis of PCF is widely used to characterize the atomic structure of amorphous materials. This method was applied for the first time to liquids and glasses
Data Loading...
