Compressibility and Structure of Silicate Melts at High Pressure

硅酸盐熔体及其结构的弹性特性不仅提供了对地球岩浆过程的深入了解，而且还提供了对地球原始分层的可能起源的深入了解。该项目将研究简单（二元）碱金属硅酸盐和锗酸盐熔体在外部加热金刚石压砧单元中原位高压和高温条件下的弹性和结构特性。弹性性能将通过布里渊光谱（光散射技术）进行研究;将采用新开发的“修改”血小板散射几何形状。结合布里渊测量，将进行拉曼研究以将测量的弹性性质与熔体的结构相关联。布里渊和拉曼研究将对具有一系列阳离子尺寸和不同熔融聚合程度的碱金属硅酸盐和发芽物进行。因此，研究人员预计，他们的数据将限制熔体弹性和压力的结构系统学，这将反过来提供洞察力的作用，压力引起的熔体结构的变化，在改变熔体的压缩性在地球内部的深度。

Manghnani EAR-0074285 The elastic properties of silicate melt and its structure provides insight into not only magmatic processes in the Earth but also into the possible origin of the planet's primordial stratification. This project will study the elastic and structural properties of simple (binary) alkali silicate and germanate melts under in-situ high pressure and temperature conditions in the externally heated diamond-anvil cell. The elastic properties will be investigated by Brillouin spectroscopy (light-scattering technique); a newly developed "modified" platelet scattering geometry will be employed. In conjunction with the Brillouin measurements, Raman studies will be conducted to correlate the measured elastic properties with the structure of the melt. The Brillouin and Raman studies will be conducted on alkali silicates and germinates with a range of cation sizes and different degrees of melt polymerization. As such, the investigators anticipate that their data will constrain the structural systematics of the melt elasticity and pressure, and this will in turn provide insight into the role of pressure-induced changes in melt structure in altering melt compressibility at depth in the Earth's interior.