Properties of Fe-bearing geomaterials at conditions close to the core-mantle boundary

在原地条件下研究造岩矿物的结构和电子性质是了解地球内部过程的关键，包括核幔边界和核形成的化学和动力学。在这个项目中，我们使用X射线发射光谱来了解电子态，并使用X射线衍射来确定材料在核幔边界条件下的相应原子结构。我们的目标也是在这些条件下开拓新方法的应用，如价到核发射和X射线拉曼散射。后者也有可能为轻元素添加结构信息。为了达到并密集地覆盖高达400 Gpa和几千K的p-T空间，我们使用了对在金刚石顶压室中压缩的材料进行X射线加热以及动态激光压缩技术。我们利用了一种新的实验设备--欧洲XFEL公司的高能量密度科学仪器。在这个项目的第一部分，我们将专注于固体材料和应用静态压缩技术。在第二阶段，我们的目标是研究熔融材料，并将应用动态压缩技术，这种技术有可能在实验室达到最高的压力和温度。我们将重点研究FeO和MgO的固溶体，即x约为0.8的(MgxFe1-xO)，因为这种矿物被认为是地球下地幔第二丰富的矿物相。

Structural and electronic properties of rock forming minerals studied at in situ conditions are the key to understand processes inside the Earth including chemistry and dynamics at the core-mantle boundary and core formation. In this project we use X-ray emission spectroscopy to learn about the electronic state and X-ray diffraction to determine the corresponding atomic structure of material at conditions of the core-mantle boundary. We aim also to pioneer the application of new methods at these conditions like valence-to-core emission and X-ray Raman scattering. Latter has the potential to add structural information also for light elements. To reach and densely cover the p-T space of up to 400 GPa and several 1000 K, we apply X-ray heating of material compressed in diamond anvil cells as well as dynamic laser compression techniques. We make use of a new experimental facility, the High-Energy Density Science instrument at the European XFEL GmbH. In the first part of this project, we will focus on solid material and apply static compression techniques. In the second phase we aim at investigating molten material and will apply dynamic compression techniques that have the potential of reaching highest achievable pressures and temperatures in the laboratory. We will focus our study on solid solutions of FeO and MgO, namely on (MgxFe1-xO) with x around 0.8 as this mineral is assumed to be the second-most abundant mineral phase of the lower mantle of the Earth.