title: NIST/Sandia/ICDD Electron Diffraction Database: A Database for Phase Identification by Electron Diffraction.
abstract: A new database containing crystallographic and chemical information designed especially for application to electron diffraction search/match and related problems has been developed. The new database was derived from two well-established x-ray diffraction databases, the JCPDS Powder Diffraction File and NBS CRYSTAL DATA, and incorporates 2 years of experience with an earlier version. It contains 71,142 entries, with space group and unit cell data for 59,612 of those. Unit cell and space group information were used, where available, to calculate patterns consisting of all allowed reflections withd-spacings greater than 0.8 A for ~ 59,000 of the entries. Calculated patterns are used in the database in preference to experimental x-ray data when both are available, since experimental x-ray data sometimes omits highd-spacing data which falls at low diffraction angles. Intensity data are not given when calculated spacings are used. A search scheme using chemistry andr-spacing (reciprocald-spacing) has been developed. Other potentially searchable data in this new database include space group, Pearson symbol, unit cell edge lengths, reduced cell edge length, and reduced cell volume. Compound and/or mineral names, formulas, and journal references are included in the output, as well as pointers to corresponding entries in NBS CRYSTAL DATA and the Powder Diffraction File where more complete information may be obtained. Atom positions are not given. Rudimentary search software has been written to implement a chemistry andr-spacing bit map search. With typical data, a full search through ~ 71,000 compounds takes 10~20 seconds on a PDP 11/23-RL02 system.
authors.affiliation: Sandia National Laboratories Albuquerque, NM 87185.
authors.forename: M J
authors.initials: MJ
authors.lastname: Carr
authors.affiliation: Sandia National Laboratories Albuquerque, NM 87185.
authors.forename: W F
authors.initials: WF
authors.lastname: Chambers
authors.affiliation: J&M Systems Albuquerque, NM 87123.
authors.forename: D
authors.initials: D
authors.lastname: Melgaard
authors.affiliation: National Institute of Standards and Technology Gaithersburg, MD 20899.
authors.forename: V L
authors.initials: VL
authors.lastname: Himes
authors.affiliation: National Institute of Standards and Technology Gaithersburg, MD 20899.
authors.forename: J K
authors.initials: JK
authors.lastname: Stalick
authors.affiliation: National Institute of Standards and Technology Gaithersburg, MD 20899.
authors.forename: A D
authors.initials: AD
authors.lastname: Mighell
keywords: electron diffraction; identification; numeric database; phase characterization