Mossbauer and Crystal Field Spectroscopy of Iron-Bearing Minerals at Ultrahigh Pressures

我们建议对铁的晶体化学进行系统的光谱研究，包括研究加压下铁在地幔和核物质中的氧化、还原、歧化和分配。主要的工具将是57Fe穆斯堡尔谱和晶场光谱分析，这些技术非常适合于含铁相的研究。结果将与拉曼散射和红外吸收光谱测量的振动光谱相关联。纽约州立大学石溪分校的多砧板仪器和地球物理实验室的钻石砧槽和活塞圆柱体仪器将用于其免费的压力范围和实验条件。光谱也将作为钻石砧座单元中压力的函数进行研究。我们将用活塞-圆柱体装置和多砧座装置将石墨/金刚石缓冲液的P-T-fO2条件映射到较低的地幔压力，并用金刚石-砧腔在超高压下映射。结果将被用来扩大现有的含铁地幔和核心材料的热力学数据库，这对模拟深部内部的矿物学、化学成分和氧化状态至关重要。

We propose to carry out a systematic spectroscopic study of the crystal chemistry of iron, including investigations of oxidation, reduction, disproportionation, and partitioning of iron in mantle and core materials at elevated pressures. The principal tools will be 57Fe Mossbauer and crystal-field spectroscopy, techniques that are ideally suited to studies of iron-bearing phases. The results will be correlated with vibrational spectra measured by Raman scattering and infrared absorption spectroscopy. The multi-anvil apparatus at SUNY Stony Brook, and diamond-anvil cell and piston-cylinder apparatus at the Geophysical Laboratory will be used for their complimentary pressure range and experimental conditions. Spectra will also be studied as a function of pressure in diamond-anvil cells. We shall map the P-T-fO2 conditions of the graphite/diamond buffer to lower mantle pressures with the piston-cylinder apparatus and the multi-anvil device and at ultrahigh pressure with the diamond-anvil cell. The results will be used to enlarge the existing thermodynamic database for iron-bearing mantle and core materials, which is crucial for modelling the mineralogy, chemical composition, and oxidation state of the deep interior.