2005 Fiscal Year Final Research Report Summary
Water Dynamics; Fluctuation and Chemical Reactions
| Project/Area Number |
14001001
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| Research Category |
Grant-in-Aid for Specially Promoted Research
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| Allocation Type | Single-year Grants |
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| Review Section |
Chemistry
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| Research Institution | Nagoya University |
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Principal Investigator |
OHMINE Iwao Nagoya University, Chemistry Department, Faculty of Science, Professor, 大学院・理学研究科, 教授 (60146719)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Shinji Institute for Molecular Science, Department of Computational Molecular Science, Professor, 自然科学研究機構・分子化学研究所, 教授 (70262847)
TANAKA Hideki Okayama University, Chemistry Department, Professor, 理学部, 教授 (80197459)
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| Project Period (FY) |
2002 – 2005
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| Keywords | water / hydrogen bond / fluctuation / freezing, melting process (phase transitions) / non linear multi dimensional spectroscopy / Raman spectroscopy / charge transfer / hydration |
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| Research Abstract |
We have addresses following five issues in " water dynamics and its diversity "
(1) Hydrogen bond network rearrangement dynamics at normal and low temperatures ; There are two liquid states in low temperature water; low - density liquids (LDL) and high - density liquids (HDL). We have made a fragment analysis to find the nature of their hydrogen bond network structures. It is found that most of LDL space is covered with only 15 types of basic fragments. Also found is that there exists the very strong structural constrains among the fragments; only a couple type fragments can attach to a given fragment. This fact explains the reason why the phase transition can exist between LDL and HDL. We have also showed how frequency-dependent heat capacity changes in the super-cooled state with temperature, and revealed its relationship of dynamics and 3D - response function of polarizability.
(2) Molecular mechanism for the crystallization and melting of water ; We have analyzed the formation of an
… More
initial nucleus and nucleation process in water freezing process by using fragment analysis. A similar analysis is applied for the melting process of ice.
(3) Theoretical analysis of non-linear multi-dimensional spectroscopy, especially 2D - Raman Spectroscopy; We have made a new theoretical analysis on 2D- Raman Spectroscopy in order to find the nature of the low-frequency motions of liquids. It is found that this method is very sensitive to the nonlinearity of dynamics so that can be applied to detect the regularity of a structure; for example, it can detect the detail mechanism of how the very small ice structure is being built and grows in the process of water freezing.
(4) Hydration structure of ions; We have made a calculation to estimate the auto-dissociation constant of water molecule and temperature dependence theoretically, and succeeded to reproduce its temperature dependence almost completely and obtain the hydration structure of the ions. From the analysis, we have found the detail mechanism of the hydration structure and the interaction, and how the long-range electron transfer takes place in this hydration process. Also found is that, when temperature rises, the stability of all energy of ionic dissociation ncreases. (This opposite to the common knowledge.) We found the physio-chemical reason for it. This finding is related to the high reactivity of supercritical water. Now, we have been investigating about hydration structure of ions near the surfaces of liquids.
(5) Reaction dynamics of proteins (biological polymer) ; Light cycle of Photoactive Yellow Proton (PYP) and the ion transport membranes; We have investigate the overall structural change of PYP and the ionic transport mechanism in a ion channel model system. Less
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Research Products
(47 results)
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[Journal Article] "Landscape of Water Dynamics and Chemical Reactions" in "New Kind of Phase Transitions : Kluwer Academic Publisher, London, Transformation in Disordered Substances" edited by V. V. Brazhkin2002
Author(s)
Ohmine, M.Matsumoto, S.Saito, A.Baba, Y.Yonekura, S.Ogasawara, H.Inagaki, C.Kobayashi
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Journal Title
Kluwer Academic Publisher, London
Pages: 613-622
Description
「研究成果報告書概要(欧文)」より
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