| Project/Area Number |
02452284
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | Nagoya University |
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Principal Investigator |
SAKATA Makoto Nagoya Univ.,Applied Phys.,Assoc.Prof.,, 工学部, 助教授 (40135306)
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| Co-Investigator(Kenkyū-buntansha) |
TAKATA M Nagoya Univ.,Applied Phys.,Assist.Prof.,, 工学部, 助手 (60197100)
HARADA J Nagoya Univ.,Applied Phys.,Prof.,, 工学部, 教授 (80016071)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1992: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1991: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1990: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Maximum Entropy Method / Electron Density / Hydrogen Bond / X-Ray Diffraction / Accurate Structure Analysis / Neutron Diffraction / Powder Diffraction / Free Atom Model / 放射光 / マキシマムエントロピ-法 / 氷の構造 / ルチル / 粉末X線回折 |
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| Research Abstract |
This scientific research aimed to investigate experimentally the pre- cise electron density distribution of hydrogen in solies. For that purpose, a new method called the Maximum Entropy Method (MEM) was developed as a part of the research. In order to establish the method, electron density distributions of various materials were obtained by applying MEM to powder X-ray diffraction data. It was found that MEM was very powerful method to visualize the accurately measured X-ray diffraction data in the form of electron densities. As for electron densities of hydrogen in solids, it was revealed that electron densities in the case of hydrogen bond distributed more like covalent bond electrons, whereas very spherical density distribu- tion of electrons were observed in the case of non-hydrogen bonding. The ionic charge of spherical distribution was found to correspond to negative ion of hydrogen. In both cases, it not appropriate to assume the distribu- tion of electrons of hydrogen in solids as a free atom. It seems that there is no justification to use the atomic form factor of hydrogen in the least squares refinement. This increases the difficulties to find the hydrogen in solids by X-ray diffraction. The precise electron density distribution of hydrogen will be observed by the Maximum Entropy Method in many materials in future.
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