Clays and Clay Minerals, Vol. 58, No. 3, 318–326, 2010.
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Authors
Yuan, Hongji
Bish, David L.
Issue Date
2010
Type
Article
Language
Keywords
Periodicals , Geology , Interstratification , NEWMOD , NEWMOD+ , X-ray diffraction
Alternative Title
Newmod+, A New Version Of The Newmod Program For Interpreting X-ray Powder Diffraction Patterns From Interstratified Clay Minerals
Abstract
NEWMOD was developed by R.C. Reynolds, Jr., for the study of two-component interstratifications of clay minerals. One-dimensional X-ray diffraction (XRD) profiles of an interstratified system of two clay minerals can be simulated using NEWMOD, given a set of parameters that describes instrumental factors, the chemical composition of the system (e.g. the concentration of Fe and interlayer cations), and structural parameters (e.g. proportions of the two components, the nature of ordering, and crystallite size distribution). NEWMOD has served as the standard method for quantitatively evaluating interstratified clay minerals for >20 y. However, the efficiency and accuracy of quantitative analysis using NEWMOD have been limited by the graphical user interface (GUI), by the lack of quantitative measures of the goodness-of-fit between the experimental and simulated XRD patterns, and by inaccuracies in some structure models used in NEWMOD. To overcome these difficulties, NEWMOD+ was coded in Visual C++ using the NEWMOD architecture, incorporating recent progress in the structures of clay minerals into a more user-friendly GUI, greatly facilitating efficient and accurate fitting. Quantitative fitting parameters (unweighted R-factor, Rp, weighted R-factor, Rwp, expected R-factor, Rexp, and chisquare, w2) are included, along with numerous other features such as a powerful series generator, which greatly simplifies the generation of multiple simulations and makes NEWMOD+ particularly valuable for teaching.
Description
gsccm58303-yua.pdf -- 436KB
Citation
Clays and Clay Minerals, Vol. 58, No. 3, 318–326, 2010.
Publisher
The Clay Minerals Society
License
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