几种不同形态冰的形态稳定形式的结构研究
C A Tulk1, C J Benmore, J Urquidi
1Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
概括
化高密度无形冰揭示了一系列复杂的中间结构形式. 这些发现表明,低温液态水相转换比以前理解的要复杂得多.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 物理化学 物理化学
背景情况:
- 无形冰,特别是高密度无形冰 (HDA),是理解水的特性的一个关键模型系统.
- 以前的研究表明存在不同的无形水相,但它们之间的结构过渡仍然不太清楚.
研究的目的:
- 为了研究高密度无形冰在回火过程中的结构演变.
- 识别和描述在转化为低密度无形冰 (LDA) 过程中形成的中间无形阶段.
- 为了了解水在低温下复杂的相位行为.
主要方法:
- 用中子衍射和X射线衍射来探测原子结构.
- 第一个衍射峰被系统地监测在各种火温度范围内.
- 计算了半径分布函数以分析结构变化.
主要成果:
- 从HDA到LDA冰的结构过渡通过一系列不同的,变态稳定的中间无形形式发生.
- 通过中子散射识别和表征了五个特定的无形相.
- 在4至8安格斯特罗姆之间的辐射分布函数中观察到系统的结构演变.
结论:
- 无形冰的回火涉及一个复杂的途径,有多个中间状态.
- 低温水中的相位转换比当前模型所表明的要复杂得多.
- 需要进一步的研究才能充分阐明水的各种无形相.
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