RUI: Thermodynamics of Nucleation: Atmospheric Aerosols from Acids, Bases, and Peptides

弗曼大学的乔治·希尔兹教授是由化学系的环境化学科学项目和大气与地球空间科学系的大气化学项目资助的。该项目的目标是研究大气中分子复合物的性质。这些分子是由水分子、硫酸分子和其他微量分子形成的。这些分子很重要，因为它们是粒子和云形成的基础。云形成的开始机制目前还不是很清楚。本科学生进行研究并获得几年的化学建模经验。该团队包括女学生和来自代表性不足的少数民族的学生。一名博士后参与研究并指导本科生。希尔兹教授与本科生研究小组（MERCURY）的研究人员长期合作。从历史上看，这些群体中约有一半的本科生进入研究生院。量子化学计算确定了最小能量结构、形成热力学和分子簇的相对丰度。作为中性和离子云凝聚核的团簇包含酸、碱和水。所考虑的酸有硫酸、甲酸和氨基酸。碱包括氨和胺。这项工作结合了配置采样的遗传算法和高效的高水平量子化学方法，到目前为止，这种方法在计算上对这种规模的系统来说是昂贵的。计算的团簇形成热力学趋势与实验成核速率进行了比较。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Professor George Shields of Furman University is supported by the Environmental Chemical Sciences Program of the Division of Chemistry and the Atmospheric Chemistry Program of the Division of Atmospheric and Geospace Sciences. The goal of the project is to examine properties of molecular complexes in the atmosphere. These molecules are formed from water molecules, sulfuric acid molecules, and other trace molecules. Such molecules are important because they are fundamental to how particles, and from these, clouds, form. The mechanism for the start of cloud formation is currently not well-understood. Undergraduate students carry out the research and gain experience in chemical modeling for several years. The team includes female students and students from underrepresented minorities. A post-doctoral associate participates in the research and the mentoring of the undergraduate students. Professor Shields has a long-standing collaboration with researchers working with undergraduate research groups, known as MERCURY. Historically, about half of the undergraduate students from these cohorts attend graduate school. The quantum chemical calculations determine the minimum energy structures, thermodynamics for formation, and relative abundance of molecular clusters. Clusters that serve as neutral and ionic cloud condensation nuclei contain acids, bases, and water. The acids considered are sulfuric acid, formic acid, and amino acids. The bases include ammonia and amines. The work combines a genetic algorithm for configurational sampling with efficient high-level quantum chemical methods that have been computationally expensive for systems of this size until now. The calculated trends in thermodynamics of cluster formation are compared with experimental nucleation rates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.