title: An insight into real and average structure from diffuse X-ray scattering - a case study.
abstract: Two-dimensional diffuse X-ray scattering from an organic salt [N-(3-(2,6-dimethylanilino)-1-methylbut-2-enylidene)-2,6-dimethylanilinium chloride, C21H27N2(+)Cl(-)] was interpreted with the help of an analytical model of diffuse scattering. An analysis of the relationship between symmetry and diffuse scattering for the studied system has been undertaken. The symmetry of the system explains the extinction pattern, taking the form of curves, on the diffuse scattering planes. We have also tested the relationship between the average structure model and scattering intensities. Two models, differing in their representation of overlapping atoms, were used. In the case of diffuse scattering the difference between resulting intensities is immense, while for the Bragg intensities it is much smaller. This sensitivity of diffuse scattering could potentially be used to improve the description of the average structure.
authors.affiliation: Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-093 Warszawa, Poland.
authors.forename: Michał Leszek
authors.initials: ML
authors.lastname: Chodkiewicz
authors.affiliation: Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-093 Warszawa, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Makal
authors.affiliation: Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-093 Warszawa, Poland.
authors.forename: Roman
authors.initials: R
authors.lastname: Gajda
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technical University, 21 Nanyang Link, 637371 Singapore, Singapore.
authors.forename: Dragoslav
authors.initials: D
authors.lastname: Vidovic
authors.affiliation: Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-093 Warszawa, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Woźniak
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray / Q000379:methods*; D008745:Methylation; D008958:Models, Molecular; D012542:Scattering, Radiation; D014965:X-Rays
chemical_list: D000814:Aniline Compounds
keywords: Ising model; X-ray diffuse scattering; occupational disorder; pair distribution function; systematic extinctions