Electron Diffraction Phase Analysis and Pattern Simulations Using the ICDD Powder Diffraction File (PDF-4+)

The Powder Diffraction File TM (PDF) is a comprehensive materials database that is the key source of reference powder diffraction data for identification and analysis of materials; from natural minerals and high-tech ceramics, to metals and alloys, and pharmaceuticals. New developments in X-ray analysis, and advances in scientific research, have dramatically influenced the range of data present in the PDF. ICDD’s premier database, PDF-4+, contains d-spacing, intensity, and hkl data used for phase identification, as well as atomic coordinates for more than 223,000 phases. In addition to being a reference database used for the analysis of traditional single phase X-ray diffraction data, the PDF-4+ also supports electron diffraction (ED) based analyses. Often in materials characterization, X-ray, electron and neutron diffraction are used to complement one another. Given the complimentary character of these techniques, it seemed only logical to compile this data into one comprehensive database, the PDF-4+. As a result, a suite of electron diffraction based simulation tools have been designed. Research scientists often use electron diffraction as a method for obtaining higher diffraction intensities of a material when X-ray scattering is limited. The increased intensity of an electron beam allows the user to investigate smaller samples and utilize a more focused beam to determine the atomic arrangement of crystals. However, the high energy beam can often promote multiple scattering interactions; making structure solution by electron diffraction alone relatively difficult compared with X-ray diffraction structure analysis. In support of the diffraction community, the ICDD has developed tools that enable users to stipulate the type of diffraction they want to reference.