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Water Dynamics; Fluctuation and Chemical Reactions

水动力学；

基本信息

批准号：
14001001
负责人：
OHMINE Iwao
金额：
$ 188.03万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Specially Promoted Research
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

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

我们在“水动力学及其多样性”中解决了以下五个问题（1）常温和低温下氢键网络重排动力学；低温水有两种液态；低密度液体（LDL）和高密度液体（HDL）。我们进行了片段分析，以找出它们氢键网络结构的性质。结果发现，大部分LDL空间仅被15种基本片段覆盖。还发现碎片之间存在很强的结构约束；只有几个类型的片段可以附加到给定的片段。这一事实解释了低密度脂蛋白和高密度脂蛋白之间可以存在相变的原因。我们还展示了过冷状态下频率相关的热容如何随温度变化，并揭示了其动力学关系和极化率的3D响应函数。(2)水结晶和熔化的分子机制；我们通过碎片分析分析了水冻结过程中初始核的形成和成核过程。类似的分析也适用于冰的融化过程。(3)非线性多维光谱，特别是二维拉曼光谱的理论分析；我们对二维拉曼光谱进行了新的理论分析，以发现液体低频运动的本质。发现该方法对动力学的非线性非常敏感，可用于检测结构的规律性；例如，它可以检测水结冰过程中微小冰结构如何形成和生长的详细机制。（4）离子的水化结构；我们从理论上估计了水分子的自解离常数和温度依赖性，并成功地几乎完全再现了其温度依赖性并获得了离子的水合结构。通过分析，我们发现了水化结构和相互作用的详细机制，以及水化过程中如何发生长程电子转移。还发现，当温度升高时，离子解离的所有能量的稳定性增加。（这与常识相反。）我们找到了其物理化学原因。这一发现与超临界水的高反应性有关。目前，我们正在研究液体表面附近离子的水合结构。(5)蛋白质(生物聚合物)的反应动力学；光活性黄质子（PYP）的光循环和离子传输膜；我们研究了 PYP 的整体结构变化和离子通道模型系统中的离子传输机制。较少的