Spectroscopic Studies of Homogeneous Precursors to Atmospheric Acids and Aerosols

一个新建造的脉冲喷嘴傅立叶变换微波光谱仪将用于测定各种气体的结构、偶极矩和反应能量，这些气体是某些大气气溶胶和酸的前体。将特别强调三氧化硫（SO3）的加合物，它是大气中硫酸（H2SO4）的直接前体。进一步的研究将集中在涉及水蒸气、三氧化硫、氨、二氧化硫、硫酸、氮氧化物和硝酸的络合物上。来自这些光谱研究的数据将为产生硫酸和硝酸气溶胶的化学机制提供新的分子水平的细节。由于气溶胶影响地球的反照率和降水模式，这项研究将影响我们对气候的理解。许多被研究的加合物都涉及到介于范德华和共价之间的化学力。因此，本研究将探讨非常规键在涉及大气重要性的假设过程中的配合物中的作用。最初项目的扩展将包括自由基中间体和选择的三级簇的研究，代表了二聚体在均匀成核过程中的下一步。

A newly constructed, pulsed-nozzle Fourier transform microwave spectrometer will be used to determine the structures, dipole moments, and reaction energetics of a variety of gaseous species that are precursors to certain atmospheric aerosols and acids. Particular emphasis will be placed on adducts of sulfur trioxide (SO3), which is the immediate precursor to sulfuric acid (H2SO4) in the atmosphere. Additional studies will focus on complexes involving water vapor, sulfur trioxide, ammonia, sulfur dioxide, sulfuric acid, nitrogen oxides, and nitric acid. The data from these spectroscopic investigations will provide new molecular-level detail about the chemical mechanisms that produce sulfuric acid and nitric acid aerosols. Because aerosols influence the earth's albedo and precipitation patterns, this research will impact our understanding of climate. Many of the adducts targeted for study are expected to involve bonding forces that are intermediate between van der Waals and covalent. Consequently, this research will explore the role of unconventional bonding in complexes involved in postulated processes of atmospheric importance. Extensions of the initial project will include studies of radical intermediates and selected tertiary clusters that represent the next step beyond dimers in the homogeneous nucleation process.