Orientational Glasses and High Pressure Phases Studied by NMR

在定向眼镜中结冰的性质目前还是一个悬而未决的问题。拟议的实验工作将调查冻结是否是随机的。温度跳跃核磁共振将被用来确定单个分子在反复熔化和冻结后是否返回到相同的方向。实验将使用研究得很好的定向玻璃氰化钾-溴化钾和氰化钠-氰化钾。这些实验应该会导致对物质玻璃态的更详细的理解。对高压下简单分子固体的研究发现了新的固相。然而，到目前为止，几乎没有一项工作研究这些固体的动力学。特别是，高压无序相中的取向无序是静态的还是动态的，目前尚不清楚。金刚石砧腔中的核磁共振是一种新发展的技术，将被用来研究取向动力学。还将测量扩散，以寻找高密度下的机制变化。这项工作将从氮气和一氧化碳开始，因为有可靠的相图，而且它们的分子相似。这项工作应该扩大对高密度材料的理解。

The nature of freezing in orientational glasses is as yet an open question. The proposed experimental work will investigate whether the freezing is random. Temperature-jump nuclear magnetic resonance will be employed to determine whether individual molecules return to the same orientation upon repeated melting and freezing. The experiments will use the well-studied orientational glasses potassium cyanide-bromide and sodium- potassium cyanide. The experiments should lead to a more detailed understanding of the glassy state of matter. Studies of simple molecular solids at high pressures have found new solid phases. However, almost none of the work to date has studied the dynamics of these solids. In particular, it is not known whether the orientational disorder in the high pressure disordered phases is static or dynamic. Nuclear magnetic resonance in diamond anvil cells, a recently developed technique, will be used to study the orientational dynamics. Diffusion will also be measured to look for a change in mechanism at high densities. The work will begin with nitrogen and carbon monoxide because reliable phase diagrams are available and because of their molecular similarities. The work should extend the understanding of high density materials.