Atmospheric Nucleation: Quantum Calculations, Kinetic Modeling, and Regional Scale Investigations

该项目力求通过以下方式增进对大气成核的了解：(1)分子团簇热力学的量子力学研究；(2)改进现有理论和开发新的成核模型；(3)将动力学模拟结果与大气成核事件的新数据进行比较；(4)全面研究羽流中颗粒的形成；(5)开发成核速率查询表，在现有的三维空气质量模型中纳入计算有效的成核模块，并调查区域尺度上的成核过程。将采用一种新的方法，将原子团簇热力学的量子力学研究与动力学成核模型相结合。该模型将用于改进和扩展现有的二元均相、三元均相和离子诱导成核理论，发展三元离子诱导成核和有机化合物促进成核的新理论。还将研究二元和三元气体混合物中的离子符号择优。将在该模型的背景下分析最近对成核前团簇、团簇离子迁移率光谱和新成核纳米粒子的带电比例的测量。将为研究生和博士后提供教育和培训机会。将在该项目下编制的成核率查询表将提供给其他调查人员。这项工作的更广泛的科学影响包括对量化气溶胶间接辐射强迫对地球气候的影响的贡献。

This project seeks to improve knowledge of atmospheric nucleation through: (1) quantum mechanical studies of the thermodynamics of molecular clusters; (2) improvement of existing theories and development of new nucleation models; (3) comparison of kinetic modeling results with new data on atmospheric nucleation events; (4) a comprehensive study of particle formation in plumes; and (5) development of nucleation rate look-up tables, incorporation of computationally efficient nucleation modules in existing 3-dimensional air quality models, and an investigation of nucleation processes at regional scales. A novel approach that integrates a quantum mechanics study of cluster thermodynamics with kinetic nucleation modeling will be employed. This model will be used to improve and extend current binary homogeneous, ternary homogeneous, and ion-mediated nucleation theories, and to develop new theories of ternary ion-mediated nucleation and the enhancement of nucleation by organic compounds. The ion sign preference in binary and ternary gaseous mixtures will also be investigated. Recent measurements of pre-nucleation clusters, mobility spectra of cluster ions, and the charged fraction of freshly nucleated nanoparticles will be analyzed in the context of the model.Education and training opportunities will be provided for graduate and postdoctoral students. Nucleation rate look-up tables to be developed under this project will be made available to other investigators. Broader scientific impacts of this work include contributions to quantification of the effects of aerosol indirect radiative forcing on Earth's climate.