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

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扩散的动力学性质：(1)水分子在羟基氧化铬表面形成均相的二维吸附，并观察到晶格气体-凝聚相(液体或固体)的平衡。本研究的主要目的是对二维临界温度(30ﾟC)以上和以下的凝聚相进行指认。根据准弹性中子散射，发现水分子在2D临界温度以下有旋转运动，但没有平移扩散。介电测量支持这一点，因为在相同的温度范围内会发生某种介电松弛。在二维临界温度(47.6ﾟC)以上的准弹性中子散射测量给出了平移扩散系数3.1*10^&lt；-10；m^2s^&lt；-1&gt；这些事实表明，吸附的pH…在2D临界温度以下，更多的是固体水。乙醇吸附与H2O吸附相比，在单层吸附中没有观察到二维冷凝，而在双层吸附中发现了特殊的缔合。(2)用准弹性中子散射、核磁共振和FT-IR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。单层水分子的C&lt；2v&gt；旋转轴偏离c轴18ﾟ。中子散射测量证实了水分子在二维受限空间中的扩散，给出了双层水的自扩散系数7.2m^2s^~(-1)。这支持了Dianoux等人提出的在受限空间中的自扩散过程的想法。通过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。氨气以分子形式和电离(铵)形式两种方式插层在层间。较少

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