RUI: Thermodynamics of Secondary Aerosol Formation: The Role of Binary and Ternary Nucleation

美国国家科学基金会化学学部的环境化学科学项目支持巴克内尔大学George C. Shields教授的一项NSF-RUI项目的研究，该项目将支持四名本科生在三个夏季进行研究，并支持一名博士后助理进行三年的研究。为了了解二次气溶胶形成的初始阶段，拟议的研究将研究大气中最重要的双星系统H2SO4-H2O。结合分子动力学采样和高水平量子化学方法，确定最小能量结构和小分子簇形成的热力学。将根据与大气有关的条件计算临界星团的大小和星团的丰度。由于二元H2SO4-H2O本身不足以解释大气中气溶胶的形成速率，因此同样的方法将应用于三元h2so4 -氨- h2o、h2so4 -胺- h2o和h2so4 -氨-胺- h2o体系，这些体系已被证明可以促进气溶胶的形成。计算出的团簇形成的热力学趋势将与主要研究者的实验合作者提供的成核速率进行比较。相当数量的本科生，包括女学生和少数民族学生，将有机会在一个高度指导的环境中与主要研究者并肩工作，进行有意义的研究项目。学生将从计算化学的强化训练中受益，并从这种经验中发展技能和对研究过程的理解，这将很好地为他们的科学事业服务。博士后助理将学习如何与本科生一起开发一个有意义和富有成效的研究项目，作为该系唯一的计算化学家，希尔兹教授将为该系的学生和教师扩大研究的范围和合作机会。

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professor George C. Shields at Bucknell University for an NSF-RUI program to support four undergraduates in a summer research experience for three summers and a postdoctoral research associate for three years. In an effort to understand the initial stages of secondary aerosol formation, the proposed research will study the most important binary system in the atmosphere, H2SO4-H2O. Combining molecular dynamics sampling and high level quantum chemical methods, the minimum energy structures and the thermodynamics of formation of small molecular clusters will be determined. The critical cluster size and abundance of the clusters will be calculated for conditions relevant to the atmosphere. As the binary H2SO4-H2O itself is not sufficient to explain aerosol formation rates in the atmosphere, the same methodology will be applied to the ternary H2SO4-ammonia-H2O, H2SO4-amine-H2O, and H2SO4-ammonia-amine-H2O systems, which have been shown to enhance the formation of aerosols. The calculated trends in thermodynamics of cluster formation will be compared with nucleation rates provided by the principle investigator's experimental collaborator. A significant number of undergraduates, including women students and minorities, will have the opportunity to work side-by-side with the principle investigator on meaningful research projects in a highly mentored environment. Students will receive and benefit from intensive training in computational chemistry, and from this experience will develop skill sets and understanding of the research process that will serve them well in their scientific careers. A postdoctoral associate will learn how to develop a meaningful and productive research program with undergraduate research students and as the only computational chemist in the department, Professor Shields will expand the exposure and scope of research and collaborative opportunities for students and faculty in the department.