High-resolution neutron diffraction studies

COMBINED NEUTRON AND X-RAY HIGH-RESOLUTION POWDER DIFFRACTION STUDIES OF CATALYSTS... 

The resurgence of interest in the field of zeolite chemistry, which has been stimulated by the appreciation of their enormous potential as catalysts, has led to the application of several sophisticated physical methods in the study of their structural properties. Important advances have already been made using high resolution, solid state NMR (1,2) and electron microscopy (3), and in this paper we discuss the scope and limitations of neutron diffraction studies with powder samples, with some specific applications to zeolite-A and synthetic faujasite. 

The total volume of protein crystals is 25—65% water, and problems that are not yet completely resolved are the nature and location of the water molecules. However, much light is being shed on the problem by high-resolution (0.12—0.18 nm 1.2-1.8 A) X-ray diffraction studies, supplemented more recently by neutron diffraction studies (Kossiakoff, 1985). Edsall and McKenzie (1983) have made a tentative classification... 

Palmer DC, Dove MT, Ibberson RM, Powell BM (1997) Stractural behavior, crystal chemistry, and phase transitions in substituted leucite High-resolution neutron powder diffraction studies. Am Mineral 82 16-29... 

Additional information on the structure of the mineral/water interface has come from neutron diffraction studies. For example, a high-resolution time-of-flight neutron diffraction study of the EDL at the vermiculite (001)/water interface (Williams et al. 

Ibberson RM, Moze O, PetriUo C (1992) High resolution neutron powder diffraction studies of the low temperature crystal structure of molecular iodine. Mol Phys 76 395-403... 

Knight KS, Bonanos N (1995) A high-resolution neutron powder diffraction study of neodymium doping in barium cerate. Solid State Ionics 77 189-194... 

M. Franjois, A. Junod, K. Yvon, A. W. Hewat, J.J. Capponi, P. Strobel, M. Marezio, P. Fischer A study of the Cu-0 chains in the high 7c superconductor YBa2Cu307 by high resolution neutron powder diffraction. Solid State Comm. 66,1117-1125 (1988)... 

Studies of hydrogen adsorption on Cu3[Co(CN)6]2 using high-resolution neutron powder diffraction showed that at 1,2 and 2.3 H2/CU loadings, the hydrogen was absorbed on two sites. The strongest adsorption site was an interstitial location within the structure. The second adsorption site was associated with exposed Cu ion coordination sites that result from the presence of [ColCN) ] vacancies. 

Compared to other biomolecular systems, lipid bilayer membranes and lyotropic lipid mesophases in general have been shown to respond most sensitively to hydrostatic pressure. The methods used in the high pressure studies have mainly included X-ray and neutron diffraction, fluorescence, IR and Raman spectroscopy, light transmission and volumetric measurements. Only a small amount of work has been performed using NMR techniques combined with high-pressure, a field which was pioneered by Jonas and co-workers " although the method is very powerful, non-invasive and allows the study of a series of structural and dynamic properties of the systems in detail and with atomic resolution. 

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