权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Elastic properties of sII clathrate hydrates and its dependence on the size of guest molecule

sII笼形水合物的弹性性质及其对客体分子大小的依赖性

基本信息

批准号：
14540298
负责人：
SASAKI Shigeo
金额：
$ 2.3万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540298/
关键词：
clathrate hydrate elastic constant high pressure DAC light scattering nitrogen hydrate Argon hydrate Krypton hydrate クラスレート・ハイドレート高圧

项目摘要

The purpose of this research is to determine the pressure dependences of elastic properties of single crystalline gas clathrate hydrates with structure II, and to clarify the mechanical stability and the host water-guest gas interaction. The results are as follows: We grew the single crystals of nitrogen hydrate, argon hydrate, krypton hydrate, and THF hydrate by using a new helium gas driven diamond anvil cell, and investigated their pressure-induced phase transformations by the visual observation through the microscope and the high-pressure Raman spectroscopy. From these results, it is found that the gas hydrates with cubic structure II are eventually transformed to the cage-less "filled ice" by way of structure H, and the pressure regions of cubic structure II for nitrogen hydrate, argon hydrate, and krypton hydrate are 0.1-0.85 GPa, 0.2-0.43 GPa, and 0.01-0.45 GPa., respectively. Moreover, we applied the high-pressure Brillouin analysis to the single crystals of argon hydrate and krypton hydrate in cubic structure II phase in order to determine their pressure dependences of elastic properties. From this analysis, we found that the elastic properties of the structure II gas hydrates are almost elastically isotropic and are similar to that of the cubic structure I methane hydrate. However, the elastic constants, the pressure dependences, and the pressure regions of structure II gas hydrates are dependent on the size of guest molecules (atoms). Therefore, the host water-guest gas interaction and the mechanical stability have relation to the size of guest molecule relative to that of host water cage.

本研究的目的是确定具有结构II的单晶气体笼形水合物的弹性性质的压力依赖性，并阐明机械稳定性和主体水-客体气体相互作用。结果如下：采用氦气驱动金刚石对顶砧生长了氮氢氧化物、氩氢氧化物、氪氢氧化物和四氢呋喃氢氧化物单晶，并通过显微镜观察和高压拉曼光谱研究了它们的压致相变。从这些结果发现，具有立方结构II的气体水合物最终通过结构H转变为无笼的“填充冰”，并且对于氮水合物、氩水合物和氪水合物，立方结构II的压力区域为0.1-0.85 GPa、0.2-0.43 GPa和0.01-0.45 GPa。分别此外，我们应用高压布里渊分析的单晶体的氩水合物和氪水合物的立方结构II相，以确定其弹性性能的压力依赖性。从这个分析中，我们发现，结构II的气体水合物的弹性性质几乎是弹性各向同性的，是类似的立方结构I甲烷水合物。然而，弹性常数，压力依赖性，和结构II的气体水合物的压力区域依赖于客体分子（原子）的大小。因此，主体水-客体气体相互作用和机械稳定性与客体分子相对于主体水笼的大小有关。