Heterogeneous Chemistry of Halogen-, Nitrogen- and Sulfur-Containing Acids and Salts

[9711970 . Castleman]该项目是对含有对大气很重要的卤素、氮和硫分子的电解质系统的研究。工作的主要重点是通过分子簇方法研究水溶液中电解质的吸收/溶解以及相关的气体到颗粒的过程。电解质体系的热化学和反应机制也将研究与大气现象高度相关的一小部分电解质体系。重点将放在卤素（作为酸的形式），卤素氧酸和盐，以及一些由氮和硫酸盐化合物组成的相关电解质种类。两种光谱方法将用于研究与电解质溶解相关的过程：(1)溶剂化时共振电子态能的变化；(2)光损耗。飞行时间质谱计系统配置适当的可调谐激光器将用于研究。该项目的结果将提供新的信息，说明通过分子聚集发生的相互竞争的化学和物理过程的相对重要性。这些非均匀过程对于理解极地平流层冰晶对大气分子的吸收，以及阐明发生在对流层下层的气体到颗粒的转化机制具有潜在的重要性。

9711970 Castleman The project is a study of electrolyte systems that contain halogens, nitrogen and sulfur molecules which are important to the atmosphere. The main focus of the work is to study the uptake/dissolution of electrolytes in aqueous systems and related gas-to-particle processes via a molecular cluster approach. The thermochemistry and reaction mechanisms of electrolyte systems will also be investigated for a smaller set of electrolyte systems which have high relevance to atmospheric phenomena. The main emphasis will be on halogens (as the acid forms), halogen oxyacids and salts, and on some related electrolyte species composed of nitrogen and sulfate compounds. Two spectroscopic approaches will be employed to study the processes associated with electrolyte dissolution: (1) resonant electronic state energy change upon solvation; and (2) photodepletion. A time-of-flight mass spectrometer system configured with appropriate tunable lasers will be used for the research. Results from the project will provide new information on the relative importance of competing chemical and physical processes that occur via molecular aggregation. These heterogeneous processes have potential importance for understanding the uptake of atmospheric molecules by polar stratospheric ice crystals, and for elucidating gas-to-particle conversion mechanisms that occur in the lower troposphere.