Marsha I. Lester

Marsha I. Lester is the Christopher H. Browne Distinguished Professor of Chemistry at the University of Pennsylvania's Department of Chemistry within the School of Arts and Sciences. Her research focuses on atmospheric chemistry and chemical reaction dynamics, particularly investigating reaction intermediates like hydroxyl radicals and Criegee intermediates using novel spectroscopic techniques. She earned her Ph.D. in Chemistry from Columbia University.

Her work has advanced understanding of atmospheric oxidation processes and has led to key discoveries about Criegee intermediates' UV absorption spectra. Lester is a member of the National Academy of Sciences and holds fellowships from the American Academy of Arts and Sciences, American Chemical Society, and American Physical Society. She has published 181 peer-reviewed articles and served as Editor-in-Chief of the Journal of Chemical Physics.

Lester collaborates extensively with faculty and students in the College of Arts and Sciences, advancing interdisciplinary research in environmental chemistry and reaction mechanisms.