Hydrogen Bonds under Extreme Conditions: Nuclear Quantum Effects and Hydrogen Bond Symmetrisation Probed with 1H-NMR in Diamond Anvil Cells

极端条件下的氢键：在金刚石砧池中用 1H-NMR 探测核量子效应和氢键对称性

• 批准号: 421754429
• 负责人: Professor Dr. Leonid Dubrovinsky, since 7/2021
• 金额: --
• 依托单位: Bayerisches Forschungsinstitut für Experimentelle Geochemie und Geophysik (BGI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/421754429?language=en
• 关键词: Hydrogen; Bonds; under; Extreme; Conditions

Hydrogen bonds are ubiquitous in nature and often influence structural and electronic properties of hydrogen bonded materials to a degree which is still not fully understood. This class of materials include numerous minerals and materials within the Earth and planetary bodies; thus, investigations of pressure effects on H-bonds are not only important for basic physics and chemistry, but also matter greatly for geo-and planetary sciences on a macroscopic "global scale". Therewith, in this proposal, rarely observedpressure induced nuclear quantum effects occurring even at ambient temperatures will be investigated on the example of high pressure ices and hydrous minerals, by means of a newly developed high pressure NMR technique in diamond anvil cells (DACs). These methods provide a singular vantage point of these exotic quantum phenomena, which cannot be detected with comparable spectroscopic methods used within the high pressure research community. To this extent, the elusive transition from high pressure ice VII to X will be investigated, which has been reported to occur between 70 and 150 GPa. Within this pressure range, the symmetric double-well potential of the hydrogen bond allows for proton tunneling across the energy barrier. Elucidation of these combined effects might answer some of the most controversial questions in modern high pressure sciences, such as the hydrogen transport into regions of Earth's interior.Hydrogen bond symmetrisation is expected to be a general feature in high-pressure behaviour of different compounds (particularly delta-AlOOH, MgSi2O6H2, FeOOH), and by studying them at megabar pressures by means of NMR (and complimentary techniques like single-crystal X-ray diffraction and vibrational spectroscopies), we expect to reveal regularities in pressure induced proton nuclear quantum effects in H-bonds.

氢键在自然界中普遍存在，并经常对氢键材料的结构和电子性质产生一定程度的影响，这一点尚不完全清楚。这类材料包括地球和行星体内的大量矿物和材料；因此，研究氢键的压力效应不仅对基础物理和化学具有重要意义，而且对地球和行星科学在宏观的“全球尺度”上具有重要意义。因此，在这个提议中，我们将以高压冰和含水矿物为例，利用新发展的金刚石顶压室(DAC)中的高压核磁共振技术，研究即使在常温下也很少观察到的压力引起的核量子效应。这些方法为这些奇异的量子现象提供了一个独特的有利位置，这是高压研究界使用的类似光谱方法无法检测到的。在这方面，将调查从高压冰VII到X的难以捉摸的过渡，据报道，这种过渡发生在70至150 Gpa之间。在这个压力范围内，氢键的对称双势能允许质子穿透能垒。阐明这些综合效应可能会回答现代高压科学中一些最具争议性的问题，如氢向地球内部的运输。氢键对称性有望成为不同化合物(特别是Delta-AlOOH，MgSi2O6H2，FeOOH)高压行为的一般特征，通过核磁共振(以及辅助技术，如单晶X射线衍射和振动光谱)在兆巴压力下对它们进行研究，我们有望揭示压力诱导氢键中质子核量子效应的规律。