Coordination of the research unit 2125

拟议研究的相关性源于我们目前对碳酸盐在高压和高温下的结构、性质和行为缺乏了解。碳酸盐是深层碳循环的重要组成部分：碳在主要地幔相中的溶解度相对较低，这意味着碳储存在辅助相中，主要是碳酸盐。量化碳循环需要识别碳交换的路径以及这些路径上的UX。因此，研究组的科学目标是了解碳酸盐的结构和性质，以及涉及高压和温度下的碳酸盐的过程。具体地说，我们想要(A)划定Ca-Mg-Fe-Sr-CO3系统中的相界，(B)观察碳酸盐与硅酸盐和氧化物的反应，(C)了解在极端条件下化合物的形成和元素分配，(E)澄清地幔条件下的结构-性质关系。为了达到这些科学目标，需要某些方法论上的发展。具体地说，我们需要完成极端条件下单晶折射研究的发展，并继续开发极端条件下的微型X射线光谱分析，在Petra III(汉堡)的光束线P02.2，在Petra III的非弹性散射光束线P01上应用高p/T X射线拉曼光谱，在弗赖贝格进行冲击波实验，以及在法兰克福和柏林进行先进的光谱分析(倍频)、时间分辨激光光谱分析(TRLFS)、相干反斯托克斯拉曼光谱分析(CARS)以及基于同步加速器的傅里叶变换红外光谱和太赫兹光谱分析。

The relevance of the proposed research stems from our current lack of knowledge about the structures, properties and behavior of carbonates at high pressures and temperatures. Carbonates are an important part of the deep carbon cycle: the solubility of carbon in dominant mantle phases is relatively low which means that carbon is stored in accessory phases, predominantly carbonates. Quantifying the carbon cycle requires identication of the pathways for carbon exchange as well as the uxes along those pathways.The scientic objectives of the Research Unit are therefore to understand structures and properties of carbonates, and of processes involving carbonates at high pressures and temperatures.Specifically we want to (a) delineate phase boundaries in the system Ca - Mg - Fe - Sr - CO3, (b) observe reactions of carbonates with silicates and oxides, (c) understand the formation of compounds and element partitioning at extreme conditions, (e) clarify structureproperty relations at mantle conditions. In order to reach these scientic objectives, certain methodological developments are required. Specically, we need to complete the development of single crystal diraction studies at extreme conditions, and to continue the development of micro X-ray uorescence at the Extreme Conditions beamline P02.2 at PETRA III (Hamburg), the application of X-ray Raman scattering spectroscopy at high p/T at the Inelastic Scattering beamline P01 of PETRA III, the developments of shock wave experiments in Freiberg and of advanced spectroscopic (second harmonic generation (SHG), time resolved laser uorescence spectroscopy (TRLFS), coherent anti-Stokes Raman spectroscopy (CARS), and synchrotron based FTIR and Terahertz spectroscopy measurements in Frankfurt and Berlin.