MEM-based structure-refinement system REMEDY and its applications

F. Izumi; S. Kumazawa; T. Ikeda; W. Z. Hu; A. Yamamoto; K. Oikawa

MEM-based structure-refinement system REMEDY and its applications

F. Izumi, S. Kumazawa, T. Ikeda, W. Z. Hu, A. Yamamoto, K. Oikawa

Global course of Engineering and Science

Research output: Contribution to journal › Conference article

78 Citations (Scopus)

Abstract

A Rietveld-analysis program RIETAN was combined with MEED for a maximum-entropy method (MEM) to grow into an integrated software REMEDY. At first, 'observed' structure factors, F_o, estimated after Rietveld analysis are analyzed by the MEM to give electron/nuclear densities biased by a structural model. Then, we evaluate structure factors, F_c(MEM), by the Fourier transform of the densities and fit the whole powder pattern calculated from the F_c(MEM) data to the observed one to refine parameters irrelevant to the structure. F_o data obtained in such a manner are analyzed again by the MEM. MEM analysis and whole-pattern fitting are alternately repeated until R factors in the pattern fitting no longer decrease. REMEDY was utilized to investigate (a) positional disorder of K⁺ ions interlayered in K_xTi_2-x/3Li_x/3O₄, (b) atomic arrangement of K clusters in K-type LTA, and (c) nuclear/electron-density distribution in HgBa₂CuO_4+δ.

Original language	English
Pages (from-to)	59-64
Number of pages	6
Journal	Materials Science Forum
Volume	378-381
Issue number	I
Publication status	Published - 2001 Dec 8
Event	7th European Powder Diffraction Conference - Barcelona, Spain Duration: 2000 May 20 → 2000 May 23

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Keywords

Electron density
Layered compound
Maximum-entropy method
Nuclear density
Superconductor
Whole-pattern fitting
Zeolite

ASJC Scopus subject areas

Materials Science(all)
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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Izumi, F., Kumazawa, S., Ikeda, T., Hu, W. Z., Yamamoto, A., & Oikawa, K. (2001). MEM-based structure-refinement system REMEDY and its applications. Materials Science Forum, 378-381(I), 59-64.

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abstract = "A Rietveld-analysis program RIETAN was combined with MEED for a maximum-entropy method (MEM) to grow into an integrated software REMEDY. At first, 'observed' structure factors, Fo, estimated after Rietveld analysis are analyzed by the MEM to give electron/nuclear densities biased by a structural model. Then, we evaluate structure factors, Fc(MEM), by the Fourier transform of the densities and fit the whole powder pattern calculated from the Fc(MEM) data to the observed one to refine parameters irrelevant to the structure. Fo data obtained in such a manner are analyzed again by the MEM. MEM analysis and whole-pattern fitting are alternately repeated until R factors in the pattern fitting no longer decrease. REMEDY was utilized to investigate (a) positional disorder of K+ ions interlayered in KxTi2-x/3Lix/3O4, (b) atomic arrangement of K clusters in K-type LTA, and (c) nuclear/electron-density distribution in HgBa2CuO4+δ.",

keywords = "Electron density, Layered compound, Maximum-entropy method, Nuclear density, Superconductor, Whole-pattern fitting, Zeolite",

author = "F. Izumi and S. Kumazawa and T. Ikeda and Hu, {W. Z.} and A. Yamamoto and K. Oikawa",

year = "2001",

month = dec

day = "8",

language = "English",

volume = "378-381",

pages = "59--64",

journal = "Materials Science Forum",

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T1 - MEM-based structure-refinement system REMEDY and its applications

AU - Izumi, F.

AU - Kumazawa, S.

AU - Ikeda, T.

AU - Hu, W. Z.

AU - Yamamoto, A.

AU - Oikawa, K.

PY - 2001/12/8

Y1 - 2001/12/8

N2 - A Rietveld-analysis program RIETAN was combined with MEED for a maximum-entropy method (MEM) to grow into an integrated software REMEDY. At first, 'observed' structure factors, Fo, estimated after Rietveld analysis are analyzed by the MEM to give electron/nuclear densities biased by a structural model. Then, we evaluate structure factors, Fc(MEM), by the Fourier transform of the densities and fit the whole powder pattern calculated from the Fc(MEM) data to the observed one to refine parameters irrelevant to the structure. Fo data obtained in such a manner are analyzed again by the MEM. MEM analysis and whole-pattern fitting are alternately repeated until R factors in the pattern fitting no longer decrease. REMEDY was utilized to investigate (a) positional disorder of K+ ions interlayered in KxTi2-x/3Lix/3O4, (b) atomic arrangement of K clusters in K-type LTA, and (c) nuclear/electron-density distribution in HgBa2CuO4+δ.

AB - A Rietveld-analysis program RIETAN was combined with MEED for a maximum-entropy method (MEM) to grow into an integrated software REMEDY. At first, 'observed' structure factors, Fo, estimated after Rietveld analysis are analyzed by the MEM to give electron/nuclear densities biased by a structural model. Then, we evaluate structure factors, Fc(MEM), by the Fourier transform of the densities and fit the whole powder pattern calculated from the Fc(MEM) data to the observed one to refine parameters irrelevant to the structure. Fo data obtained in such a manner are analyzed again by the MEM. MEM analysis and whole-pattern fitting are alternately repeated until R factors in the pattern fitting no longer decrease. REMEDY was utilized to investigate (a) positional disorder of K+ ions interlayered in KxTi2-x/3Lix/3O4, (b) atomic arrangement of K clusters in K-type LTA, and (c) nuclear/electron-density distribution in HgBa2CuO4+δ.

KW - Electron density

KW - Layered compound

KW - Maximum-entropy method

KW - Nuclear density

KW - Superconductor

KW - Whole-pattern fitting

KW - Zeolite

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M3 - Conference article

AN - SCOPUS:4243573479

VL - 378-381

SP - 59

EP - 64

JO - Materials Science Forum

JF - Materials Science Forum

SN - 0255-5476

IS - I

T2 - 7th European Powder Diffraction Conference

Y2 - 20 May 2000 through 23 May 2000

ER -

MEM-based structure-refinement system REMEDY and its applications

Abstract

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Keywords

ASJC Scopus subject areas

Cite this

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