研究室詳細はこちら

坂倉輝俊
助教
Terutoshi SAKAKURA
Assistant Professor
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
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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
単結晶 X 線回折法における技術開発
Technical study of single-crystal X-ray diffraction
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
multiple-diffractions (MDs) are eliminated, single-crystal XRD can capture spatial distribution of even only one
valence electron in crystals.
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.
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.
Acta Cryst. B,67,193(2011).
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,
ISOTOPES 誌, 60(3),131 (2011).
Acta Cryst. E,66,i68(2010).
[email protected]
http://db.tagen.tohoku.ac.jp/php/forweb/outline.php?lang=ja&no=4015
Fig.3. Electron density of ψ(t2g2,1A1)
orbital illustrated by inverse Fourier
transformation of structure factor
calculated
by
our
developing
wave-function
based
refinement
software for a virtual crystal
isostructural to YTiO3.
Acta Cryst E,66,i80(2010).

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