Microscopic observation and in-situ Raman scattering studies on high-pressure phase transformations of Kr hydrate.
Microscopic observation and in-situ Raman scattering studies on high-pressure phase transformations of Kr hydrate.
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DOI：
10.1021/jp0606309
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发表时间：
2006-05
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影响因子：
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通讯作者：
S. Sasaki;Shinsuke Hori;T. Kume;H. Shimizu
中科院分区：
文献类型：
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作者：
S. Sasaki;Shinsuke Hori;T. Kume;H. Shimizu
在5.2 GPa和296K的压力下对合成的单晶Kr水合物进行了直接显微镜观察和原位拉曼散射测量。观察到Kr水合物的初始立方结构II(SII)在0.45、0.75和1.8 GPa时依次转变为立方结构I(Si)、六方结构和正交形结构(所谓的“填充冰”)。SO相至少存在至5.2 GPa.除了这些转变外，我们还发现了1.0 GPa时的新相行为，这很可能是由于客体Kr原子在没有结构变化的情况下改变了主体水笼的笼子占有率所致。拉曼散射测量表明，在Si的压力区，130 cm(-1)左右的晶格振动峰消失，这使我们能够区分Si相、SiI相和Sh相。
Direct observations through a microscope and in-situ Raman scattering measurements of synthesized single-crystalline Kr hydrate have been performed at pressures up to 5.2 GPa and 296 K. We have observed that the initial cubic structure II (sII) of Kr hydrate successively transforms to a cubic structure I (sI), a hexagonal structure, and an orthorhombic structure (sO) called "filled ice" at 0.45, 0.75, and 1.8 GPa, respectively. The sO phase exists at least up to 5.2 GPa. In addition to these transformations, we have also found the new phase behavior at 1.0 GPa, which is most likely caused by the change of cage occupancy of host water cages by guest Kr atoms without structural change. Raman scattering measurements for observed phases have shown that the lattice vibrational peak at around 130 cm(-1) disappears in the pressure region of sI, which enables us to distinguish the sI phase from sII and sH phases.