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大原 高志; 鬼柳 亮嗣; 中尾 朗子*; 宗像 孝司*; 石川 喜久*; 森山 健太郎*
no journal, ,
In structure analysis of molecular crystals, single-crystal neutron diffraction is a powerful technique that can reliably observe molecular structures, including hydrogen atoms. However, it requires a large single-crystal, and consequently, the measurement time is often insufficient for the sample size. On the other hand, the structural information of non-hydrogen atoms is usually determined with high accuracy by single-crystal X-ray diffraction. Therefore, in some cases, it is still acceptable if structural information regarding only the hydrogen atoms of interest can be obtained from neutron diffraction data with accuracy in line with the research objectives, even when the measurement time is not enough for the full-matrix refinement. In this study, we generated pseudo-short-measurement-time diffraction data from raw diffraction data measured with a single-crystal diffractometer SENJU in MLF. Subsequently, we evaluated the structural parameters of hydrogen atoms obtained from these data with structural information obtained by X-ray diffraction.
大原 高志; 鬼柳 亮嗣; 中尾 朗子*; 宗像 孝司*; 石川 喜久*; 森山 健太郎*; 田村 格良; 金子 耕士
no journal, ,
SENJU at J-PARC is a TOF single-crystal neutron diffractometer designed for precise crystal and magnetic structure analyses under multiple extreme environments, such as low-temperature, high-pressure and high-magnetic field, as well as for taking diffraction intensities of small single crystals with a volume of less than 1.0 mm
down to 0.1 mm. Recently, we added four area detectors to SENJU in the obliquely downward direction of the sample position. The additional detectors can cover the blind region in the reciprocal space when measuring a low-symmetry sample and improve the measurement efficiency of low-symmetric molecular crystals. While the primary target materials of SENJU are inorganic crystals such as oxides or alloys, numerous structural studies of molecular crystals have been performed, and many scientific results have been achieved. In this presentation, we show the current situations of diffraction measurements of molecular crystals at SENJU.
大原 高志
no journal, ,
J-PARC/MLFでは現在2台の単結晶回折計が稼働している。これらの回折計ではパルス中性子の特徴を利用したtime-of-flight(TOF) Laue法によって広い逆空間を一度にスキャンできるため、J-PARCの大強度中性子と相まって従来に比べて小さい0.5mm角程度の単結晶試料を用いた測定が現実的なビームタイムで可能となった。加えて、SENJUでは極低温(
4K)や磁場(7T)環境下での測定が可能であり、高温や高圧、電場といった様々な試料環境の整備も進めている。これにより、これまで結晶サイズの問題から測定を諦めざるを得なかった様々な機能性有機・有機金属結晶の単結晶中性子構造解析を、その機能が発現する環境下で実現できると期待される。本講演ではJ-PARCの単結晶中性子回折計を活用した結晶化学の最新状況を紹介する。