Comparison and evaluation of pair distribution functions, using a similarity measure based on cross-correlation functions

  • An approach for the comparison of pair distribution functions (PDFs) has been developed using a similarity measure based on cross-correlation functions. The PDF is very sensitive to changes in the local structure, i.e. small deviations in the structure can cause large signal shifts and significant discrepancies between the PDFs. Therefore, a comparison based on pointwise differences (e.g. R values and difference curves) may lead to the assumption that the investigated PDFs as well as the corresponding structural models are not in agreement at all, whereas a careful visual inspection of the investigated structural models and corresponding PDFs may reveal a relatively good match. To quantify the agreement of different PDFs for those cases an alternative approach is introduced: the similarity measure based on cross-correlation functions. In this paper, the power of this application of the similarity measure to the analysis of PDFs is highlighted. The similarity measure is compared with the classical Rwp values as representative of the comparison based on pointwise differences as well as with the Pearson product-moment correlation coefficient, using polymorph IV of barbituric acid as an example.

Download full text files

Export metadata

Author:Stefan HabermehlORCiD, Carina Schlesinger, Dragica Prill
Parent Title (English):Journal of applied crystallography
Place of publication:Oxford
Document Type:Article
Date of Publication (online):2021/02/11
Date of first Publication:2021/02/11
Publishing Institution:Universit├Ątsbibliothek Johann Christian Senckenberg
Release Date:2021/08/04
Tag:R values; cross-correlation functions; pair distribution functions; similarity measures; total scattering techniques
Page Number:12
First Page:612
Last Page:623
Institutes:Biochemie, Chemie und Pharmazie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung 4.0