Diffusion in Crystalline Ice Measured Using Laser Resonant Desorption Techniques

本研究项目由分析和表面化学计划支持，解决了冰样品中杂质分析和扩散的问题。科罗拉多大学的Steven M. George教授和他的同事将激光共振解吸深度分析方法应用于非均质大气化学和冰芯分析中重要的物种分析。特别是，与大气化学过程有关的卤化氢、硝酸、各种阳离子、含硫分子和弱酸和弱碱是本研究的主题。使用内部高压分析单元，加上负载锁定系统，可以分析环境冰样品，正在检查一系列冰样品中这些杂质的位置和扩散。这项工作的结果对发展包括非均质过程在内的精确大气模式，以及对冰川冰芯及其环境条件历史记录的理解具有重要意义。对臭氧损耗和全球变暖等环境过程的理解依赖于对大气冰样品和冰川冰芯中微量分子的位置和运动的详细测量。本研究项目的工作重点是开发高空间分辨率的激光解吸方法，以准确和精确地分析这类环境冰样品。这项工作的结果对于我们对大气的理解至关重要，无论是在当代还是在地球的地质历史上。

This research project, supported by the Analytical and Surface Chemistry Program, addresses the question of impurity analysis and diffusion in ice samples. Professor Steven M. George and his colleagues at the University of Colorado apply laser resonant desorption depth profiling methods to the analysis of species important in heterogeneous atmospheric chemistry and ice core analysis. In particular, hydrogen halides, nitric acid, various cations, sulfur containing molecules, and weak acids and bases implicated in atmospheric chemical processes are the subject of this investigation. Using an internal high pressure analysis cell, coupled with a load lock system to enable the analysis of environmental ice samples, the location and diffusion of these impurities in a range of ice samples are being examined. The results of this work are of significant importance to the development of accurate atmospheric models which include heterogeneous processes, as well as to the understanding of glacial ice cores and their historical record of environmental conditions. The understanding of environmental processes such as ozone depletion and global warming rely on the availability of detailed measurements of the location and motion of trace molecules in atmospheric ice samples and in glacial ice cores. The work of this research project is focussed on developing high spatial resolution laser desorption methods for the accurate and precise analysis of these sorts of environmental ice samples. The results of this work are crucial to our developing understanding of the atmosphere, both in current times and across the geological history of the earth.