Pair distribution function analysis of molecular compounds: significance and modeling approach discussed using the example ofp-terphenyl

2012 ◽  
Vol 45 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Nadine Rademacher ◽  
Luke L. Daemen ◽  
Eric L. Chronister ◽  
Thomas Proffen
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Short Range ◽  
Short Range Order ◽  
Function Analysis ◽  
Structural Models ◽  
Range Order ◽  
Molecular Systems ◽  
The Common ◽  
Molecular Compounds

Modeling the pair distribution function (PDF) of molecular compounds is a challenging task because intra- and intermolecular interactions lead to very different features in the PDF. This article discusses the different peak shapes in PDFs of molecular compounds in detail. Moreover, the common methods to calculate PDFs from structural models are summarized and evaluated with respect to molecular systems and an approach to calculate PDFs from molecular crystals more accurately is introduced.p-Terphenyl was chosen as a test compound. It adopts a crystal structure with disordered features and short-range order. The short-range order was previously investigated by analyzing single-crystal diffuse scattering and it was also extracted from experimental PDFs during this study.

Determination ofB-cation chemical short-range order in perovskites from the total pair-distribution function

2008 ◽  
Vol 41 (2) ◽  
pp. 386-392 ◽  
Author(s):  
Victor Krayzman ◽  
Igor Levin
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Short Range ◽  
Short Range Order ◽  
Structural Models ◽  
Range Order ◽  
Cation Order ◽  
Powder Samples ◽  
Complex Perovskites

Short-rangeB-cation order affects the functional properties of many complex perovskites. However, current ability to measure the characteristics of such chemical short-range order (SRO) in perovskite-structured ceramics is limited. In the present study, two distinct methods are compared for the determination of theB-cation SRO parameters from the total scattering pair-distribution function (PDF). Both methods rely on reverse Monte Carlo refinements of the structural models but differ in the procedures used to extract the SRO characteristics. The accuracy of these methods was tested using synthetic PDF data generated for models of prototype Ca(Zr,Ti)O3solid solutions. One of the approaches developed in the present study, which proved to yield the most accurate results, was used to analyze the SRO of Ti and Zr in powder samples of Ca(Zr,Ti)O3.

scholarly journals Chemical short range order obtained from the atomic pair distribution function

2002 ◽  
Vol 217 (2) ◽  
Author(s):  
Th. Proffen ◽  
V. Petkov ◽  
S. J. L. Billinge ◽  
T. Vogt
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Short Range ◽  
Short Range Order ◽  
Structural Information ◽  
Range Order ◽  
Crystalline Materials ◽  
X Ray ◽  
Atomic Pair Distribution Function ◽  
Atomic Pair

AbstractMany crystalline materials show chemical short range order and relaxation of neighboring atoms. Local structural information can be obtained by analyzing the atomic pair distribution function (PDF) obtained from powder diffraction data. In this paper, we present the successful extraction of chemical short range order parameters from the x-ray PDF of a quenched Cu

Short Range Order in Structural Models for the Amorphous Fe80B20- and Ni81B19-Alloys

1988 ◽  
Vol 43 (12) ◽  
pp. 1047-1054 ◽  
Author(s):  
P. Kizler ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Correlation Functions ◽  
Amorphous Alloys ◽  
Short Range ◽  
Short Range Order ◽  
Bond Angle ◽  
Pair Correlation ◽  
Structural Models ◽  
Range Order ◽  
Pair Correlation Functions

The short range order in several structural models for amorphous alloys is investigated with respect to pair correlation functions, bond angle distributions and other properties. Despite of the different principles of modelling, the topological short range order turned out to be almost identical. Therefore also the question for the triplet correlations to some extent is found solved. Remaining differences thus consist regarding more complex correlations among the atoms.

Magnetic pair distribution function analysis: introduction and applications

2014 ◽  
Vol 70 (a1) ◽  
pp. C1459-C1459
Author(s):  
Benjamin Frandsen ◽  
Xiaohao Yang ◽  
Simon Billinge
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Short Range ◽  
Magnetic Order ◽  
Function Analysis ◽  
Real Space ◽  
Magnetic Scattering ◽  
Magnetic Correlations ◽  
Range Magnetic Order ◽  
Magnetic Pair

Short-range magnetic correlations play a crucial role in a variety of condensed matter phenomena, yet they remain notoriously difficult to investigate experimentally. Quantitative analysis of the diffuse scattering of neutrons from local magnetic correlations represents a viable but challenging route toward revealing short-range magnetic order in complex materials. Reverse Monte Carlo techniques that iteratively fit randomly generated structural models in momentum space have been used successfully [1], demonstrating that diffuse magnetic scattering can be rich in information. Recently [2], we developed a real-space approach to investigating local magnetic correlations, which we call magnetic pair distribution function (mPDF) analysis in analogy to the more familiar atomic pair distribution function. This experimentally accessible quantity reveals magnetic correlations directly in real space and places diffuse and Bragg scattering on equal footing, thereby gaining sensitivity to both short- and long-range magnetic order. Here we present the basic theory behind mPDF analysis and provide several examples of its utility using both simulated and experimentally measured data on several interesting magnetic systems, including a canonical antiferromagnetic, a spin glass, and a spin ice. We discuss the potential impact that mPDF methods may have on current and future research interests in magnetism.

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