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On the dynamics and phase properties of water molecules spread over 2D space

关于散布在二维空间中的水分子的动力学和相特性

基本信息

批准号：
08454227
负责人：
KITTAKA Shigeharu
金额：
$ 4.29万
依托单位：
Okayama University of Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

Dynamic properties of water molecules spread in a two-dimensional field were studied by applying the quasi-elastic neutron scattering spectroscopy, dielectric measurements, and NMR measurements.(1) On a hydroxylated chromium oxide surface water molecules are adsorbed by forming the homogeneous two-dimensional phase, in which lattice gas-condensed phase (liquid or solid) equilibrium is observed. Main purpose of the present study is to assign the condensed phase above and below the 2D-critical temperature (30ﾟC). According to the quasi-elastic neutron scattering there found rotational motion of water molecules below the 2D critical temperature but no translational diffusion. Dielectric measurements supported this with the fact that some kind of dielectric relaxation occurs in the same temperature range. Quasi-elastic neutron scattering measurements above 2D critical temperature (47.6ﾟC) gave translational diffusion coefficient 3.1*10^<-10> m^2s^<-1>. These facts indicate that adsorbed ph … More ase below the 2D critical temperature is a solid water. Alcohol adsorption was done comparatively with the H_2O adsorption, in which two-dimensional condensation was not observed in a monolayr but special association was found in double layr range. Monte Carlo simulations for the adsorption of water and methanol using the program Cerius2 gave the structure different from the one presumed from the IR measurements.(2) Dynamic properties of interlayr water molecules in the layred vanadium pentoxide hydrate were studied by quasi-elastic neutron scattering, NMR,and FT-IR.C_<2v> rotation axis of monolayr water molecule leans from c-axis by 18ﾟ. Neutron scattering measurements substantiate that water molecules diffuse in a two dimensionally confined space and give the self-diffusion coefficient 7.2m^2s^<-1> for double layr water. This supports the idea proposed by Dianoux et al for the self-diffusion process in a confined space. Analysis of the diffusion observed by adsorption rate measurements suggested that the diffusion path of the particle ranges a few mm. Ammonia was intercalated between the layrs in two modes, molecular and ionized (ammonium) forms. Less

利用准弹性中子散射谱、介电测量和核磁共振测量研究了水分子在二维场中的动力学性质。(1)在羟基化的氧化铬表面上，水分子通过形成均匀的二维相而被吸附，在该二维相中观察到晶格气凝相（液体或固体）平衡。本研究的主要目的是指定高于和低于二维临界温度（30 ℃）的凝聚相。根据准弹性中子散射，在二维临界温度以下发现了水分子的旋转运动，但没有平移扩散。介电测量支持这一事实，即在相同的温度范围内发生某种介电弛豫。在二维临界温度（47.6摄氏度）以上的准弹性中子散射测量得到平移扩散系数为3.1*10^<-10>m^2s^<-1>。这些事实表明吸附的ph ...更多信息低于二维临界温度的水是固态水。乙醇吸附与水吸附相比，在单层范围内未观察到二维凝聚，而在双层范围内观察到特殊的缔合。使用程序Cerius2对水和甲醇的吸附进行了Monte Carlo模拟，得到了与IR测量推测的结构不同的结构。(2)用准弹性中子散射、核磁共振和傅立叶变换红外光谱研究了层状五氧化二钒水合物中层间水分子的动力学性质<2v>。中子散射测量证实了水分子在二维有限空间中的扩散，并给出了双层水的自扩散系数为7.2m^2s^<-1>。这支持了Dianoux等人提出的在有限空间中的自扩散过程的想法。吸附速率测量观察到的扩散分析表明，颗粒的扩散路径范围为几毫米。氨被插入层之间的两种模式，分子和离子化（铵）的形式。少