NIST/Sandia/ICDD Electron-Diffraction Database - A database for phase identification by electron-diffraction

Journal Article · Sun Jan 01 00:00:00 EST 1989 · Journal of Research of the National Bureau of Standards

DOI:https://doi.org/10.6028/jres.094.003· OSTI ID:1628717

Carr, M. J. ^[1]; Chambers, W. F. ^[1]; Melgaard, D. ^[2]; Himes, V. L. ^[3]; Stalick, J. K. ^[3]; Mighell, A. D. ^[3]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2. J&M Systems Albuquerque, NM (United States)
3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)

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 with flf-spacings greater than 0.8 Å 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 xray data sometimes omits high d-spacing data which falls at low diffraction angles. Intensity data are not given when calculated spacings are used. A search scheme using chemistry and r-spacing (reciprocal rf-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 and /--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.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1628717
• Journal Information: Journal of Research of the National Bureau of Standards, Vol. 94, Issue 1; ISSN 0160-1741
• Publisher: National Bureau of Standards
• Country of Publication: United States
• Language: English

Related Subjects

97 MATHEMATICS AND COMPUTING
47 OTHER INSTRUMENTATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Instruments & Instrumentation
Physics
electron diffraction
identification
numeric database
phase characterization