Acquisition of a Laser Raman Spectrometer for Studies on Phase Transition and Melting Silicate Minerals and Glasses at Ultra-high Temperature.

该合同提供了购买时间分辨激光拉曼光谱仪系统一半费用的资金，该系统将在华盛顿大学地质科学系安装和运行。华盛顿大学承诺提供所需的剩余一半。该仪器系统将用于研究固态相变和硅酸盐在高达3000K温度下熔化的微观机制和动力学。样品的局部加热将涉及连续功率CO2激光器的辐射，硅酸盐晶体或玻璃作为自己的坩埚容器。高温下来自样品的强烈黑体辐射将使用包含脉冲激发和门控阵检测的同步检测技术进行抑制。样品温度将通过斯托克斯/反斯托克斯比率和双色光学高温计从拉曼强度确定。高温拉曼光谱将通过分子动力学模拟来解释。高温下硅酸盐的分子水平结构是解释地球内部熔融和其他相变性质的重要数据。

This award provides funds for one-half the cost of acquiring a time-resolved laser Raman spectrometer system that will be installed and operated in the Department of Geological Sciences at the University of Washington. The University of Washington is committed to providing the remaining half required. The instrument system will be used to study the microscopic mechanism and dynamics of solid-state phase transitions and of melting in silicates at temperatures up to 3000K. Localized heating of the sample will involve radiation by a continuous- power CO2 laser, with the silicate crystals or glass acting as its own crucible container. Intense black-body radiation from the sample at high-temperature will be suppressed using a synchronous detection technique that involves pulsed-excitation and gated-array detection. The sample temperature will be determined from Raman intensities by Stokes/antiStokes ratioing and by means of a two color optical pyrometer. The high- temperature Raman spectra will be interpreted by molecular dynamics simulations. The molecular level structures of silicates at high-temperature are vital data for interpreting the nature of melting and other phase transitions inside the Earth.