Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-22T23:21:40.975Z Has data issue: false hasContentIssue false

New neutron time-of-flight (TOF) capability in PDF-4+ relational databases: digitized diffraction patterns and I/Ic for quantitative phases analysis

Published online by Cambridge University Press:  03 May 2017

J. Faber*
Affiliation:
Faber Consulting, Thornton, Pennsylvania
S. Kabekkodu
Affiliation:
International Centre for Diffraction Data (ICDD), Newtown Square, Pennsylvania
J. Blanton
Affiliation:
International Centre for Diffraction Data (ICDD), Newtown Square, Pennsylvania
T. Blanton
Affiliation:
International Centre for Diffraction Data (ICDD), Newtown Square, Pennsylvania
T. Fawcett
Affiliation:
International Centre for Diffraction Data (ICDD), Newtown Square, Pennsylvania
*
a)Author to whom correspondence should be addressed. Electronic mail: [email protected]

Abstract

The PDF-4+ 2016 contains 271 449 entries with atomic coordinates that can be used to calculate neutron time-of-flight (TOF) powder diffraction patterns. These diffraction patterns can all be calculated on-the-fly. Three TOF results can be realized: the live calculation of on-the fly diffraction patterns, the population of static PDF® entries, and data for search/match tables for phase identification. In connection with search/match, we have extended the development of the I/Ic formalism to include both constant wavelength (CW) and TOF neutron diffraction data. It is shown that the wavelength dependence of X-ray and CW neutron data must be factored into the behavior of I/Ic, whereas this dependence is directly incorporated into TOF data.

Type
Technical Articles
Copyright
Copyright © International Centre for Diffraction Data 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bacon, G. E. (1975). Neutron Diffraction (Clarendon Press, Oxford), 3rd ed., pp. 140152.Google Scholar
Faber, J. (2004) “ICDD's new PDF-4 organic database: search indexes, full pattern analysis and data mining,” Cry St. Rev. 10, 97107.Google Scholar
Faber, J. and Fawcett, T. (2002). “The powder diffraction file: present and future,” Acta Crystallogr. B58, 325332.CrossRefGoogle Scholar
Faber, J., Crowder, C., Blanton, J., Kabekkodu, S., Gourdon, O., Blanton, T., and Fawcett, T. (2014). “New neutron diffraction data capability in the PDF-4+ 2014 relational database,” Adv. X-ray Anal. 58, 7789.Google Scholar
Hubbard, C. R., Evans, E. H., and Smith, D. K. (1976). “The reference intensity ratio, I/I c for computer simulated powder patterns,” J. Appl. Crystallogr. 9, 169174. The literature citations in this reference are particularly extensive.Google Scholar
Larson, A. C. and Von Dreele, R. B. (2000). General Structure Analysis System (GSAS) (Los Alamos National Laboratory Report LAUR 86-748).Google Scholar
Toby, B. H. (2001). “EXPGUI, a graphical user interface for GSAS,” J. Appl. Crystallogr. 34, 210213.Google Scholar
Thompson, P., Cox, D. E., and Hastings, J. B. (1987). Rieveld refinement of Debye-Scherrer synchrotron X-ray data from Al2O3. J. Appl. Cryst. 20, 7983.Google Scholar
Visser, J. W. and Wolff, P. M. (1964). Absolute Intensities (Report 641.109). Technisch Physische Dienst, Delft, Netherlands.Google Scholar