Precise implications for real-space pair distribution function modeling of effects intrinsic to modern time-of-flight neutron diffractometers
Abstract
Total scattering and pair distribution function (PDF) methods allow for detailed study of local atomic order and disorder, including materials for which Rietveld refinements are not traditionally possible (amorphous materials, liquids, glasses and nanoparticles). With the advent of modern neutron time-of-flight (TOF) instrumentation, total scattering studies are capable of producing PDFs with ranges upwards of 100–200 Å, covering the correlation length scales of interest for many materials under study. Despite this, the refinement and subsequent analysis of data are often limited by confounding factors that are not rigorously accounted for in conventional analysis programs. While many of these artifacts are known and recognized by experts in the field, their effects and any associated mitigation strategies largely exist as passed-down `tribal' knowledge in the community, and have not been concisely demonstrated and compared in a unified presentation. This article aims to explicitly demonstrate, through reviews of previous literature, simulated analysis and real-world case studies, the effects of resolution, binning, bounds, peak shape, peak asymmetry, inconsistent conversion of TOF to d spacing and merging of multiple banks in neutron TOF data as they directly relate to real-space PDF analysis. Suggestions for best practice in analysis of data from modern neutron TOF total scattering instruments when using conventional analysis programs are made, as well as recommendations for improved analysis methods and future instrument design.
Additional Information
© Daniel Olds et al . 2018. Received 6 July 2017. Accepted 23 February 2018. The authors acknowledge Ashfia Huq, Matthew G. Tucker, Peter F. Peterson and Ramya Deshpande for their helpful discussions related to this article. This work was supported under the Department of Energy Office of Basic Energy Sciences Laboratory Directed Research and Development (LDRD) Program at Oak Ridge National Laboratory LDRD No. 8420 (simulation and analysis) and the BES Early Career Award: Exploiting Small Signatures: Quantifying Nanoscale Structure and Behavior KC04062. Research conducted at the NOMAD and POWGEN beamlines at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Sciences, US Department of Energy under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. Research conducted on NPDF at the Lujan Center was funded by DOE Office of Basic Energy Sciences. LANL is operated by Los Alamos National Security LLC under DOE contract No. DE-AC52-06NA25396.Attached Files
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Additional details
- Eprint ID
- 86865
- Resolver ID
- CaltechAUTHORS:20180606-160356581
- LDRD 8420
- Oak Ridge National Laboratory
- KC04062
- Department of Energy (DOE)
- DE-AC05-00OR22725
- Department of Energy (DOE)
- DE-AC52-06NA25396
- Department of Energy (DOE)
- Created
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2018-06-07Created from EPrint's datestamp field
- Updated
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2023-06-01Created from EPrint's last_modified field