Acquisition of Optical Second Harmonic Generation Instrumentation for the Study of Molecular Adsorption at the Mineral/Water Interface

这笔拨款提供了部分支持，用于购买用于开发光学二次谐波产生（SHG）仪器的组件，以研究矿物表面吸附有机分子的分子结构。结合怀俄明大学现有的扫描探针显微镜（EAR-9634143），该技术可以获得前所未有的单晶表面特异性矿物表面吸附有机物取向的信息。在分析矿物-流体界面的分子结构方面（如x射线吸收光谱和傅立叶变换红外光谱），SHG比其他分析技术有显著的优势，最重要的是它可以在原位、大气压和非粉末样品上使用。了解流体-岩石地球化学相互作用的原子尺度结构是研究矿物溶解/生长和环境污染物命运的基础。因此，矿物表面化学的分析进展是我们理解紧迫的环境问题的前沿。为此，SHG的发展应该促进我们对表面电场的pH依赖性，分子吸附和取向，以及矿物表面氧化还原中心的基本电子转移性质的认识。＊＊＊

9725993 Eggleston This grant provides partial support of the costs of acquiring components to develop optical second harmonic generation (SHG) instrumentation to study molecular structure of adsorbed organic molecules on mineral surfaces. Coupled with the existing scanning probe microscope (EAR-9634143) at the University of Wyoming, this technique could yield unprecedented information on the orientation of adsorbed organics on mineral surfaces with single-crystal face specificity. SHG promises significant advantages over other analytical techniques for the analysis of molecular structure at mineral-fluid interfaces (i.e. X-ray absorption spectroscopy and Fourier transform infrared spectroscopy), the most important being that is useable in situ, at atmospheric pressure, and on non-powdered samples. Knowledge of the atomic-scale structure of fluid-rock geochemical interactions is fundamental to studies of mineral dissolution/growth and the fate of environmental pollutants. Therefore, analytical advances in mineral surface chemistry are at the frontier of our understanding of problems of pressing environmental significance. To that end, development of SHG should advance our knowledge of the pH dependency of surface electric fields, molecular adsorption and orientation, and fundamental electron transfer properties of redox centers at mineral surfaces. ***