A new approach to the determination of the uncertainty in neutron diffraction experiments with isotopic substitution method

Imre Bakó, Gábor Pálinkás, Tamás Grósz, Szabolcs Bálint, Gergely Tóth, Tamás Radnai

Research output: Contribution to journalArticle

Abstract

Neutron diffraction experiment with isotopically substituted substances is a powerful approach claiming to yield unambiguous information about the local atomic structure in disordered materials. This information is expressed in the partial structure factors, and extracting them from a series of measurements requires solution of a set of linear equations that is affected by experimental errors. In this article, we suggest a method for the determination of the optimal set of H/D compositions with or without taking into account the experimental error. For the case of water, our investigations show that the selection of the isotope concentrations and the distribution of measurement time among the various samples have a critical role if one wants to utilize the limited neutron beam time efficiently. It is well known that measurements of pure H2O introduce fairly large errors in the partial structure factors due to its very strong incoherent scattering. In water and methanol as examples, we investigated the propagation of random errors to the partial structure factors using partial pair-correlation functions from molecular dynamics simulation. It is shown in the example of water that it is not worthwhile to measure pure H2O.

Original languageEnglish
Pages (from-to)5-10
Number of pages6
JournalJournal of Molecular Liquids
Volume198
DOIs
Publication statusPublished - Oct 2014

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Keywords

  • Estimation of uncertainty
  • Experimental uncertainty
  • Neutron diffraction isotopic substitution
  • Systems of linear equations

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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