Atmospheric and Interfacial Reaction Dynamics

在过去的资助期内，我们在与水、冰、灰尘和“城市污垢”表面的非均匀大气化学有关的几个领域取得了重大进展。我们将pH敏感荧光探针的激发和发射光谱与激光诱导荧光结合使用，以确定水和冰界面的pH值，并使用该测量来跟踪那里的反应。我们已经优化了我们的扫瞄角度拉曼探针，并使用这些探针来探测硝酸盐阴离子在液体和冷冻水面上分配的倾向，以及卤化物阴离子的存在如何影响这种分配。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发生在水、灰尘、有机和“城市污垢”表面的光敏反应。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应用的小组。在下一个资助期内，我们将继续发展创新的想法和技术，并将为大气模型提供定量的动力学和光化学参数。特别是，我们将重点了解在空气-冰和空气-“污垢”界面观察到的非常不同的反应性的基础。我们将继续探索有机单层涂层在影响水表面化学方面的作用。我们将推进我们的想法，如何光化学在水界面可能会敏感地影响或“调谐”通过调整化学环境。我们将继续通过光化学方法研究大气矿物粉尘对其局部氧化环境的影响。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发生在单个液滴中的化学反应——这在大气研究中是第一次——并将反射-吸收红外光谱纳入我们的表面探测工具套件中。

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.