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.
