Unified view for pressure-induced successive changes from amorphization to re-entrant crystallization

压力引起的从非晶化到重入结晶的连续变化的统一视图

• 批准号: 16540343
• 负责人: FUCHIZAKI Kazuhiro
• 金额: $ 0.96万
• 依托单位: Ehime University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540343/
• 关键词: pressure; structural phase transition; amorphization; molecular crystal; cluster; optimization; polymerization

A new idea of "thermodynamic optimization for spatial configuration among elements with variable size" is proposed. On the basis of this idea the reporter has tried to explain a series of structural changes induced by uploading pressure. To this end, a molecular crystal tin tetraiodide was chosen as a prototype substance, which undergoes pressure-induced amorphization followed by re-entrant crystallization. If tin atoms are assumed to occupy the tetrahedral interstitial sites of the host lattice made of iodines, frustration will come up in finding possible occupation sites as far as the tin does always take four iodines as nearest neighbors. According to this rule the lower-pressure phase structure automatically appears as a case without any frustration. However, frustration develops with increasing tin population. The local energy of the frustrated site becomes higher as compared to nonfrustated site. The Hamiltonian can then be written down by suitably assigning the local energies. T … More he series of structural variations were thus qualitatively explained by minimizing the free energy obtained through the Hamiltonian.The idea can be adapted to describe the physical origin of polyamorphism. It is naturally inferred that a pressure-induced liquid-to-liquid transition will take place in tin tetraiodide. In fact, from the melting curve of the low-pressure crystalline phase was found to have a break at around 1.5 GPa, beyond which the melting curve becomes almost flat. This suggests that the density of the low-pressure liquid differs from that on the higher-pressure side. Finally, we have succeeded in showing direct evidence for the existence of the two liquids with different local structures by conducting in situ synchrotron x-ray diffraction experiments. The present idea yields, when treated within mean-field approximation, a regular solution treatment. The phase diagram of tin tetraiode was constructed within this framework, which included a new critical point and spinodal lines. Less

提出了“可变尺寸元素间空间构型的热力学优化”的新思路，在此思路的基础上，记者试图解释由上传压力引起的一系列结构变化。选择四碘化锡作为原型物质，它会经历压力诱导的非晶化，然后再进入结晶。如果假设锡原子占据由碘组成的主晶格的四面体间隙位点，则会出现挫败感。在寻找可能的占据位置时，锡总是以四个碘作为最近邻，根据该规则，低压相结构会自动出现，而不会出现任何挫折。然而，随着当地能量的增加，挫折就会出现。与非受挫位点相比，受挫位点的值变得更高，然后可以通过适当分配局部能量 T … More 来写出一系列结构变化，从而通过最小化通过哈密顿量获得的自由能来定性地解释。可以适应描述了多晶现象的物理起源，可以自然地推断出四碘化锡中会发生压力诱导的液体到液体的转变。事实上，从低压结晶相的熔化曲线发现在 处有一个中断。大约 1.5 GPa，超过这个值，熔化曲线几乎变得平坦，这表明低压液体的密度与高压侧的密度不同。最后，我们成功地证明了存在的直接证据。通过进行原位同步加速器 X 射线衍射实验，在平均场近似下，对两种具有不同局部结构的液体进行了常规固溶处理，其中包括一个四碘化锡的相图。新的临界点和旋节线更少。

项目成果

Effect of octupole-octupole interactions of on the thermodynamic stability of the low-pressure crystalline state of SnI_4 molecular crystal

八极-八极相互作用对SnI_4分子晶体低压晶态热力学稳定性的影响

• 发表时间: 2004
• 期刊: Solid State Communications 132
• 作者: F.Matsubara;T.Shirakura;S.Takahashi;Y.Baba;Kazuhiro Fuchizaki;Kazhiro Fuchizaki;Kazuhiro Fuchizaki;渕崎員弘;Kazuhiro Fuchizaki;Kazuhiro Fuchizaki
• 通讯作者: Kazuhiro Fuchizaki

圧力誘起非晶質化の発現機構

压力诱导非晶化的机理

• 发表时间: 2004
• 期刊: 日本板硝子材料工学助成会誌 22
• 作者: F.Matsubara;T.Shirakura;S.Takahashi;Y.Baba;Kazuhiro Fuchizaki;Kazhiro Fuchizaki;Kazuhiro Fuchizaki;渕崎員弘
• 通讯作者: 渕崎員弘

Murnaghan's Equation of State Revisited

穆纳汉状态方程重温

• 发表时间: 2006
• 期刊: Journal of Physical Society of Japan 75
• 作者: F.Matsubara;T.Shirakura;S.Takahashi;Y.Baba;Kazuhiro Fuchizaki
• 通讯作者: Kazuhiro Fuchizaki

Effect of octupole-octupole interactions on the thermodynamic stability of the low-pressure crystalline state of SnI_4 molecular crystals

八极-八极相互作用对SnI_4分子晶体低压晶态热力学稳定性的影响

• 发表时间: 2004
• 期刊: Solid State Communications 132
• 作者: F.Matsubara;T.Shirakura;S.Takahashi;Y.Baba;Kazuhiro Fuchizaki;Kazhiro Fuchizaki;Kazuhiro Fuchizaki;渕崎員弘;Kazuhiro Fuchizaki;Kazuhiro Fuchizaki;Kazuhiro Fuchizaki;Kazuhiro Fuchizaki;Kazuhiro Fuchizaki;K.Fuchizaki;K.Fuchizaki
• 通讯作者: K.Fuchizaki

Physical Mechanism of Pressure-Induced Amorphization

压力诱导非晶化的物理机制

• 发表时间: 2004
• 期刊: Nippon Sheet Glass Foundation for Materials Science and Engineering Report 22
• 作者: F.Matsubara;T.Shirakura;S.Takahashi;Y.Baba;Kazuhiro Fuchizaki;Kazhiro Fuchizaki;Kazuhiro Fuchizaki;渕崎員弘;Kazuhiro Fuchizaki;Kazuhiro Fuchizaki;Kazuhiro Fuchizaki
• 通讯作者: Kazuhiro Fuchizaki