RUI: Collaborative Research: Quantifying the Interfacial Partitioning and the Structural Modifications of Polyatomic Ions in Model Aerosol Systems

Christopher Newport University, Newport News VA

Investigators

Abstract

This project is funded by the Environmental Chemical Science Program (ECS) of the Chemistry Division. It represents a collaboration between Professor Joshua D. Patterson of the Department of Molecular Biology and Chemistry at Christopher Newport University and Professor Arunkumar Sharma of the Physical Sciences Department at Wagner College. They use a combined experimental and computational approach to study the properties of ions containing many atoms (polyatomic ions). Ions are found in large concentrations in aerosol particles throughout the atmosphere. These ions participate in reactions that often take place in the boundary of atmospheric aerosol particles. This project aims to improve understanding of these reactions. The structures and availabilities of the ions within the boundary region of model aerosols are determined. The research is carried out by the investigators and their undergraduate students. The students who participate in the project gain experience in physical, computational, and atmospheric chemistry. The students participate in an exchange program between the two institutions and receive training in the complementary disciplines. This training broadens the undergraduate research experience and builds synergy between the computational and experimental elements of the project. Heterogeneous reactions that occur in aerosol particles are of critical importance to the atmosphere. They are a crucial component of chemical reaction cycles linked to Arctic and Antarctic ozone loss, tropospheric ozone production, and acid rain. Despite the importance of these reactions, the ability to predict their outcomes is limited by the complexity of the environment where these reactions occur. Interfaces have unique chemical properties that cannot be described by gas or liquid properties. The preferential allocation of ions to the interface, a process not observed in liquids, is believed to have a strong impact on heterogeneous reactions. This project utilizes spectroscopic and computation methods to examine the structures of polyatomic ions. Interfacial properties (affinity, interfacial-core partitioning, and ion depth) are quantified. The approach uses reverse micelles (aqueous droplets in a non-polar liquid) as model systems for atmospheric aerosols. The quantification of the interfacial properties of polyatomic ions improves our knowledge of heterogeneous chemistry and the predictive accuracy of atmospheric chemistry models.