Inelastic neutron scattering evidence for anomalous H-H distances in metal hydrides
Inelastic neutron scattering evidence for anomalous H-H distances in metal hydrides
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DOI：
10.1073/pnas.1912900117
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发表时间：
2020-02-25
影响因子：
11.1
通讯作者：
Ramirez-Cuesta, Anibal J.
中科院分区：
文献类型：
--
作者：
Borgschulte, Andreas;Terreni, Jasmin;Ramirez-Cuesta, Anibal J.
含氢材料具有基础性和技术性的意义。对于这两种材料来说，一个突出的问题是可以掺入这些材料中的氢的量，因为这极大地决定了它们的物理性质，如电子和晶体结构。金属中氢原子的数量由氢与金属的相互作用和氢-氢相互作用控制。已经确定的是，在环境条件下，常规金属氧化物中最小可能的氢-氢距离约为2.1埃，尽管对于高压下的材料，更近的H-H距离是可能的。我们提出了非弹性中子散射测量氢在ZrV 2 Hx显示非预期的散射在低能量转移。光谱的分析表明，这些光谱特征部分源于氢的振动，这些振动被邻近的氢限制在1.6埃的距离内。这些距离比相关的距离小得多，因此违反了所谓的Switendick准则。这些结果对设计和创建具有其他特性和应用的纳米材料具有一定的意义。
Hydrogen-containing materials are of fundamental as well as technological interest. An outstanding question for both is the amount of hydrogen that can be incorporated in such materials, because that determines dramatically their physical properties such as electronic and crystalline structure. The number of hydrogen atoms in a metal is controlled by the interaction of hydrogens with the metal and by the hydrogen-hydrogen interactions. It is well established that the minimal possible hydrogen-hydrogen distances in conventional metal hydrides are around 2.1 angstrom under ambient conditions, although closer H-H distances are possible for materials under high pressure. We present inelastic neutron scattering measurements on hydrogen in ZrV2Hx showing nonexpected scattering at low-energy transfer. The analysis of the spectra reveals that these spectral features in part originate from hydrogen vibrations confined by neighboring hydrogen at distances as short as 1.6 angstrom. These distances are much smaller than those found in related hydrides, thereby violating the so-called Switendick criterion. The results have implications for the design and creation of hydrides with additional properties and applications.