Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Wang, Chuji

Committee Member

Pierce, Donna

Committee Member

Ariunbold, Gombojav

Committee Member

Arnoldus, Henk

Committee Member

Pradhan, Prabhakar; Pan, Yong-Le

Date of Degree

8-7-2025

Original embargo terms

Visible MSU Only 1 year

Document Type

Dissertation - Campus Access Only

Major

Engineering

Degree Name

Doctor of Philosophy (Ph.D.)

College

James Worth Bagley College of Engineering

Department

Department of Physics and Astronomy

Abstract

This dissertation explores the combined technique of optical trapping and Raman spectroscopy (OT-RS) to study the physical and chemical properties, as well as the dynamic surface changes, of single aerosol particles in air. The study covers a wide range of aerosol types, including bioaerosols (such as pollen, bacteria, and fungi), dust particles (such as black carbon, terrestrial, and extraterrestrial materials), and liquid droplets (such as sea-spray aerosols). The optical trapping system used in this work is based on the universal optical trap (UOT), which is capable of trapping and manipulating a wide variety of particle types. These include both transparent and absorbing particles, solid and liquid forms, and particles with either uniform or heterogeneous structures. The property of these trapped particles is influenced by their continuous interactions with the surrounding environment. By trapping single aerosol particles over time, the chemical and physical dynamic changes that occur on particle surfaces as they interact with air and trace gases are investigated in this dissertation. A particular focus of this study is the heterogeneous chemistry of mercury (Hg) within aerosol particles. Heterogeneous chemistry is complex and challenging to study using traditional methods. With OT-RS, the signal of Hg in single airborne particles can be detected, and its chemical reactions with air and trace gases can be monitored. This dissertation demonstrates that OT-RS is a powerful tool for studying not only the static properties of aerosol particles but also their dynamic surface changes and heterogeneous chemistry, including gas–particle reactions such as gas–liquid and gas–solid interactions, at the single-particle level.

Sponsorship (Optional)

Army Research Office, and National Science Foundation.

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