IMRAM

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

東北大学
多元物質科学研究所

LAST UPDATE 2017/02/26

  • 研究者氏名
    Researcher Name

    坂倉輝俊 Terutoshi SAKAKURA
    助教 Assistant Professor
  • 所属
    Professional Affiliation

    東北大学多元物質科学研究所
    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

    計測研究部門
    Division of Measurements
  • 研究キーワード
    Research Keywords

    単結晶X線結晶構造解析
    電子密度分布
    多重散乱
    波動関数
    Single-crystal X-ray diffraction
    Electron density distribution
    Multiple diffraction
    Wave function
研究テーマ
Research Subject
単結晶 X 線回折法における技術開発
Technical study of single-crystal X-ray diffraction

研究の背景 Background

物質内の電子密度をとても明瞭に捉える新しい技術が今日必要とされています。原理上、そのような分析手法として最も有力なのは単結晶X線回折法です。多重散乱等のあらゆるノイズを除去する事ができれば、単結晶X線回折法を用いて結晶内のたった一個の価電子の空間分布までも捉える事が可能となります。

Novel techniques to capture electron densities in materials quite clearly are required nowadays. In principle, the most promising probe of this kind is single-crystal X-ray diffraction (XRD). If any kinds of contaminations such as multiplediffractions (MDs) are eliminated, single-crystal XRD can capture spatial distribution of even only one valence electron in crystals.

研究の目標 Outcome

波動関数ベースのデータ解析ソフトウェアや多重散乱を抑える測定法の開発をする事で、古くからのX線回折技術は結晶内の電子密度を測定する優れたツールへと変わり得ます。この分野におけるこのような技術的困難や煩雑さを克服していくことを研究の目標としています。

Through the development of wave-function-based refinement software and data collection technique reducing contaminations due to multiple diffractions, conventional XRD technique can become a sophisticated tool to investigate electron density distribution in crystals. Our objective is to overcome such technical difficulties and complexities in this field.

研究図Research Figure

Fig.1. Comparison of structure factor squared measured in MD-avoided and no MD-avoided methods for YMn2O5. For weak or forbidden reflections, most of the no MD-avoided reflections are larger than MD-avoided ones in a few orders due to MD. Fig.2. Experimentally observed orbital order of Ti-3d1 electrons in YTiO3. For no MD-avoided measurement (b), lobes of 3d electrons, which is clearly observed in MD-avoided measurement (a), cannot be observed. Isosurface level is ±1.3eÅ-3. Sky-blue is negative and yellow is positive, Fig.3. Electron density of ψ(t2g2,1A1) orbital illustrated by inverse Fourier transformation of structure factor calculated by our developing wavefunction based refinement software for a virtual crystal isostructural to YTiO3.

文献 / Publications

Acta Cryst. B,67,193(2011). ISOTOPES 誌, 60(3),131 (2011). Acta Cryst. E,66,i68(2010). Acta Cryst E,66,i80(2010).

研究者HP