Journal of Research of the National Institute of Standards and Technology articles from January 2004

Journal of Research of the National Institute of Standards and Technology archives from January 2004

Accuracy in Powder Diffraction III--Part 1: preface.
January 1, 2004... With the continuing advancements in the powder diffraction technique, a broad-based review conference was warranted. Accordingly the IUCr Commission on Powder Diffraction, in conjunction with the National Institute of Standards and Technology...

Fundamental parameters line profile fitting in laboratory diffractometers.
January 1, 2004... The fundamental parameters approach to line profile fitting uses physically based models to generate the line profile shapes. Fundamental parameters profile fitting (FPPF) has been used to synthesize and fit data from both parallel beam and...

Polycapillary optics for materials science studies: instrumental effects and their correction.
January 1, 2004... The instrumental effects related to the use of a polycapillary x-ray lens as primary beam collimator are here studied and the features observed in the measurements modelled via Monte-Carlo ray-tracing. Comparison with existing procedures is...

Direct space structure solution applications.
January 1, 2004... The crystal structures of 2,4,6-triisopropylbenzenesulfonamide, 1,2,3-trihydroxybenzene-hexamethylenetetramine (1/1), 5-bromonicotinic acid and chlorothalonil form II have been solved from x-ray powder diffraction data, by application of a...

Diffraction line broadening analysis if broadening is caused by both dislocations and limited crystallite size.
January 1, 2004... The determination of dislocation distribution parameters is discussed for specimens where both strain broadening caused by dislocations and size broadening occur. If the strain broadening is well described by a model due to Wilkens, several...

X-ray spectrometry of copper: new results on an old subject.
January 1, 2004... We review recent, and some less recent, measurements of several emission spectra of copper. The results are discussed with special emphasis on elucidating the structure of the K[[alpha].sub.1,2] and K[[beta].sub.1,3] diagram lines and their...

Multidataset refinement resonant diffraction, and magnetic structures.
January 1, 2004... The scope of Rietveld and other powder diffraction refinements continues to expand, driven by improvements in instrumentation, methodology and software. This will be illustrated by examples from our research in recent years. Multidataset...

Powder diffraction: least-squares and beyond.
January 1, 2004... This paper addresses some of the underlying statistical assumptions and issues in the collection and refinement of powder diffraction data. While standard data collection and Rietveld analysis have been extremely successful in providing...

Direct methods optimised for solving crystal structure by powder diffraction data: limits, strategies, and prospects.
January 1, 2004... The ab-initio crystal structure solution by powder diffraction data requires great efforts because of the collapse of the experimental information onto the one dimensional 2[theta] axis of the pattern. Different strategies will be described...

The high resolution powder diffraction beam line at ESRF.
January 1, 2004... The optical design and performance of the high-resolution powder diffraction beam line BM16 at ESRF are discussed and illustrated. Some recent studies carried out on BM16 are described, including crystal structure solution and refinement,...

Global Rietveld refinement.
January 1, 2004... Global optimisation methods of structure determination from powder diffraction data have risen to prominence in a relatively short space of time and they now constitute a key approach in the examination of polycrystalline molecular organic...

Bayesian inference of nanoparticle-broadened x-ray line profiles.
January 1, 2004... A single-step, self-contained method for determining the crystallite-size distribution and shape from experimental x-ray line profile data is presented. It is shown that the crystallite-size distribution can be determined without invoking a...