Neutron Diffraction and Its Application

Neutron Diffraction and Its Application in Inorganic Chemistry G. E. Bacon... 

Neutron diffraction and its applications in inorganic chemistry. G. E. Bacon, Adv. Inorg. Chem. Radiochem., 1966, 8,225-256 (74). 

In a paper by Albinati and Willis (1982) the application of the Rietveld method in neutron and X-ray powder diffraction was discussed considering the different experimental techniques of obtaining the diffraction patterns. For a detailed description of the method and its applications see a reference publication (Young 1995). See also Jenkins and Snyder (1996). A frequently used calculation program for the... 

LHPM a Computer Program for Rietveld Analysis of X ray and Neutron Powder Diffraction Patterns, R. J. Hill, and C. J. Howard (1986) AAEC Report No. Ml 12 and QPDA A User Friendly, Interactive Program for Quantitative Phase and Crystal Size/Strain Analysis of Powder Diffraction Data, I. C. Madsen and R. J. Hill, Powder Diffr., 1990, 5, 195 199 A Rietveld analysis program RIETAN 98 and its applications to zeolites, F. Izumi and T. Ikeda, Mater. Sci. Forum, 2000, 321-324, 198 203 and F. Izumi, Development and Applications of the Pioneering Technology of Structure Refinement from Powder Diffraction Data, J. Ceram. Soc. Jpn., 2003, 111, 617 623... 

Wright AC, Cole JM, Newport RJ, Fisher CE, Clarke SJ, Sinclair RN, Fischer HE, Cuello GJ (2007) The neutron diffraction anomalous dispersion technique and its application to vitreous Sm203-4P205. Nucl Instrum Methods Phys Res Sect A 571(3) 622-635... 

The correlation functions provide an alternate route to the equilibrium properties of classical fluids. In particular, the two-particle correlation fimction of a system with a pairwise additive potential detemrines all of its themiodynamic properties. It also detemrines the compressibility of systems witir even more complex tliree-body and higher-order interactions. The pair correlation fiinctions are easier to approximate than the PFs to which they are related they can also be obtained, in principle, from x-ray or neutron diffraction experiments. This provides a useful perspective of fluid stmcture, and enables Hamiltonian models and approximations for the equilibrium stmcture of fluids and solutions to be tested by direct comparison with the experimentally detennined correlation fiinctions. We discuss the basic relations for the correlation fiinctions in the canonical and grand canonical ensembles before considering applications to model systems. 

Recent progress in electron diffraction has significantly broadened its applications from a primary a microstructure characterization tool to an accurate structure analysis technique that traditionally belongs almost exclusively to the domain of X-ray and neutron diffraction. This development is timely since the focus of modem materials feature size is increasingly on nanoscale stmctures, where the electron high spatial... 

During the last five years, a powerful new method of getting crystal structural information from powder diffraction patterns has become widely used. Known variously as the Rietveld method, profile refinement1, or, more descriptively, whole-pattern-fitting structure refinement, the method was first introduced by Rietveld (X, 2) for use with neutron powder diffraction patterns. It has now been successfully used with neutron data to determine crystal structural details of more than 200 different materials in polycrystalline powder form. Later modified to work with x-ray powder patterns (3, X) the method has now been used for the refinement of more than 30 crystal structures, in 15 space groups, from x-ray powder data. Neutron applications have been reviewed by Cheetham and Taylor (5) and those for x-ray by Young (6). 

For the type of structures with which we are concerned in this article this is the important application. The detection of hydrogen by X-ray diffraction is always difficult and never accurate. It is important to know the precise positions of the hydrogen atoms in many aromatic molecules where some degree of overcrowding must exist, and this information can probably only be obtained by neutron diffraction. Already accurate studies of hydrogen positions have been made for... 

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