From parallel to single crystallization kinetics in high-density amorphous ice
From parallel to single crystallization kinetics in high-density amorphous ice
复制标题
高密度非晶冰中从平行结晶动力学到单结晶动力学
DOI：
10.1103/physrevb.88.174105
复制
发表时间：
2013
影响因子：
3.7
通讯作者：
T. Loerting
中科院分区：
文献类型：
--
作者：
M. Seidl;K. Amann;P. Handle;G. Zifferer;T. Loerting
采用粉末X射线衍射和压差法比较了未退火（uHDA）和膨胀（eHDA）高密度非晶冰在0.20 GPa压力下的等压相变行为。eHDA显示出高的热稳定性并且仅结晶成单一冰相，而uHDA显示出低得多的热稳定性并且总是结晶成冰相的混合物。出乎意料的是，在低温下，六边形冰首先从uHDA生长，而这个阶段从来没有从eHDA结晶。这使我们得出结论，隐藏的结构秩序的纳米晶域的形式存在于uHDA，这触发了六角冰的生长。相比之下，这些有序域是不存在的eHDA，这似乎是一种均匀的材料，因此，可以被认为是一个候选人的低温代理提出的高密度液相的水。目前的工作为进一步的实验研究提供了基础，旨在调查这种可能性，因为它确定了充分研究的uHDA不是在这种情况下研究的正确材料，而最近发现的eHDA是。
The isobaric transformation behavior of unannealed (uHDA) and expanded (eHDA) high-density amorphous ice at pressures up to 0.20 GPa is compared using powder x-ray diffraction and dilatometry. eHDA shows high thermal stability and crystallizes to a single ice phase only, whereas uHDA shows much lower thermal stability and always crystallizes to a mixture of ice phases. Unexpectedly, at low temperatures hexagonal ice grows first from uHDA, whereas this phase never crystallizes from eHDA. This leads us to conclude that hidden structural order in the form of nanocrystalline domains is present in uHDA, which triggers growth of hexagonal ice. By contrast, these ordered domains are absent in eHDA, which appears to be a homogeneous material and, thus, could be considered as a candidate for the low-temperature proxy of the proposed high-density liquid phase of water. The present work provides the basis for further experimental studies aiming at investigating this possibility since it establishes that the well-studied uHDA is not the right material to be studied in this context, whereas the more recently discovered eHDA is.