Atmospheric and Interfacial Reaction Dynamics

在过去的资助期间，我们在与水、冰、灰尘和“城市污垢”表面的异质大气化学有关的几个领域取得了重大进展。我们已经使用了激发和发射光谱的pH敏感的荧光探针结合切角激光诱导荧光，以确定pH值在水和冰的界面，并使用这种测量跟踪反应。 我们已经优化了我们的掠射角拉曼探针，并使用这些来探测硝酸根阴离子的倾向，分配到液体和冷冻水表面，以及如何存在的卤素阴离子影响这种分区。我们继续探索各种单层有机涂层对空气-水界面化学过程反应的影响。我们已经证明并探索了在水，灰尘，有机物和“城市污垢”表面发生的光敏反应。在大多数这些努力中，我们是第一个报告该技术或其在大气化学中的用途的小组。 在下一个资助期内，我们将继续发展创新的想法和技术，并将提供用于大气模型的定量动力学和光化学参数。 特别是，我们将集中在理解的基础上观察到的空气冰和空气“污垢”界面的非常不同的反应性。我们将继续探索有机单层涂层在影响水性表面化学方面的作用。我们将推进我们的想法，如何在水界面的光化学可能会受到敏感的影响或“调谐”通过调整化学环境。我们将继续研究大气矿物粉尘通过光化学影响其局部氧化环境的作用。 在这些研究中，我们将开发和利用更多的新工具。特别是，我们将利用声悬浮来研究单个液滴中发生的化学反应-这是大气研究中的第一次-并将反射吸收红外光谱法纳入我们的表面询问工具套件中。

Over the past funding period we have made significant progress in several areas related to heterogeneous atmospheric chemistry of aqueous, ice, dust and "urban grime" surfaces. We have used excitation and emission spectra of pH-sensitive fluorescent probes in conjunction with lancing-angle laser-induced fluorescence to determine pH at water and ice interfaces and used this measurement to track reactions there. We have optimized our glancing-angle Raman probes and used these to probe the propensity of nitrate anion to partition to the liquid and frozen water surface, and how the presence of halide anions affects this partitioning. We have continued to explore the influence of various monolayer organic coatings on chemical processes reactions at the air-water interface. We have demonstrated and explored photosensitized reactions occurring at water, dust, organic and "urban grime" surfaces. In most of these endeavours, we have been the first group to report the technique or its use in atmospheric chemistry. During the next funding period we will continue to develop innovative ideas and techniques and will provide quantitative kinetic and photochemical parameters for use in atmospheric models. In particular, we will focus on understanding the basis for the very different reactivities observed at the air-ice and air-"grime" interfaces. We will continue to explore the role(s) which organic monolayer coatings play on influencing aqueous surface chemistry. We will push forward our ideas on how photochemistry at aqueous interfaces may be sensitively affected or "tuned" by tuning the chemical environment there. We will continue to study the roles of atmospheric mineral dust in influencing their local oxidation environment via photochemistry. In these studies we will develop and utilize more new tools. In particular we will utilize acoustic levitation to study chemistry occurring in single droplets -a first in atmospheric studies - and will incorporate reflection-absorption IR spectroscopy into our suite of tools for surface interrogation.