Heterogeneous Atmospheric Chemistry: Elucidating the Importantce of Reactions Involving Aqueous Droplets and Ice Crystals Through Cluster Research

该项目旨在确定各种机制， 量化大气重要非均质的比率 流程. 这些过程的全部范围包括 分子从气态到凝聚态的转移， 新颗粒形成或通过吸附或溶解到 微滴或气溶胶颗粒，连同伴随的 化学转化 这些过程可以用来去除 从而改变它们的寿命， 和去除过程，同时影响它们的 进一步参与气相反应，并增强这些反应， 在凝聚态中是可能的。 当前的主旨 建议是关于旨在阐明 涉及包含液体的含水体系的反应 与（某些）气溶胶、云滴和冰有关的介质 晶体通过集群的调查。 一些关键性的实验将在每一个 上述领域，包括旨在阐明 水相中的转化和各种 中性和离子种类。 拟议的研究分为四个一般领域。 第一个方面，也是我们将重点强调的方面， 深入研究涉及水分子簇的反应， 无论是纯的还是含有其他成分的，沿着重要的 大气分子和自由基 调查 水和其他分子之间的混合团簇系统， 盐和酸，沿着确定的作用， 各种共簇物种的结构和键合，将 也要承担。 第二个领域，与 前面提到的，涉及热化学的研究 混合集群。 这方面的主要目标是， 工作是提供数据，从其中确定部分 与液滴相互作用的组分的压力（与 活性系数）。 第三方面的工作涉及 研究了光对反应的影响， 在第一个领域很重要。 第四项活动是 一个计算阶段的程序致力于阐明 结构和成键的集群物种中确定的其他 该计划的三个阶段至关重要， 反应和活度系数。 计算 团簇的振动频率和有关动力学方面 将有助于解释拟议的 前三个领域的研究。

This project is directed to identifying the mechanisms and quantifying the rates of atmospherically important heterogeneous processes. The full range of these processes includes the transfer of molecules from the gaseous to the condensed state by new particle formation or by adsorption onto or dissolution into a microdroplet or aerosol particle, together with concomitant chemical conversion. These processes can serve to remove species from the gas phase, thereby altering their lifetimes, transport and removal processes, and at the same time influencing their further participation in gas phase reactions and enhancing those possible in the condensed phase. The thrust of the present proposal is on studies designed to elucidate the mechanisms of reactions which involve aqueous systems comprising the liquid media associated with (some) aerosols, cloud droplets and ice crystals through an investigation of clusters. Some critical experiments will be conducted in each of the aforementioned areas, including work designed to elucidate transformations in aqueous phases and the influence of various neutral and ionic species. The proposed studies are subdivided into four general areas. The first, to which major emphasis will be given, constitutes an in-depth investigation of reactions involving water clusters, both pure and containing other constituents, along with important atmospheric molecules and free radicals. An investigation of mixed cluster systems between water and other molecules such as salts and acids, along with a determination of the role of various co-clustered species on the structure and bonding, will also be undertaken. The second area, which is related to the aforementioned, involves an investigation of the thermochemistry of mixed clusters. The primary objective of this aspect of the work is to provide data from which to determine the partial pressure of constituents interacting with droplets (related to activity coefficients). The third aspect of the work involves studies of the influence of light on the reactions identified to be important in the first area. The fourth activity constitutes a calculational phase of the program devoted to elucidating the structure and bonding of cluster species identified in the other three phases of the program as being of critical importance to the reactions and the activity coefficients. Calculations of vibrational frequencies and related dynamical aspects of clusters will be of value in interpreting the results of the proposed studies in the first three areas.