Elizabeth Garrett
MIT Department: Chemistry
Faculty Mentor: Prof. Troy Van Voorhis
Research Supervisor: Leah Weisburn, Minsik Cho
Undergraduate Institution: College of the Holy Cross
Website:
Biography
Elizabeth is a senior Chemistry major and Urban Studies minor at College of the Holy Cross. She conducted research under Dr. Avila-Bront for two years on characterizing binary organothiol self-assembled monolayers. During a gap semester she taught math and English to girls in Peru and traveled through Australia and New Zealand, experiences that strengthened her adaptability and deepened her interest in environmental issues.These experiences sparked her passion for sustainable chemistry, especially solar cell development, and expanding girls’ access to STEM. To advance her training in physical chemistry, Elizabeth currently researches at MIT with Dr. Van Voorhis, modeling low-energy conformations of iron-sulfur clusters with potential for nitrogen fixation. In Fall 2025, she will conduct environmental research in Cambodia, studying climate challenges in one of the world’s most vulnerable regions. She plans to pursue a PhD focused on renewable energy solutions, integrating technical insight with a global, community-informed perspective.
Abstract
Iron-Sulfur Cluster Modeling Through Constrained Density Functional Theory
Elizabeth Garrett1, Leah Weisburn2, Minsik Cho2, Weiming Shi2, Daniel Suess2, and Troy Van Voorhis2
1Department of Mechanical Engineering, Johns Hopkins University
2Department of Aeronautics and Astronautics, Massachusetts Institute of Technology
Iron-sulfur ([Fe4S4]) clusters are essential cofactors in biological redox chemistry, notably in nitrogen fixation. Compared to current industrial standards, which are extremely energy-intensive and emit large amounts of CO2, it is no wonder that researchers seek to mimic nature to find sustainable alternatives. These clusters show promise as industrial catalysts, but mimicking their reactivity is challenging. Many excited states are thermally accessible at room temperature, leading to significant temperature-dependent reactivity; therefore, accurate modeling must account for both ground and excited states.
Constrained density functional theory (CDFT) and constrained density functional theory- configuration interaction (CDFT-CI) were employed to model dominant spin and charge states. CDFT enables control over localized charges and spin states on each Fe ion, while CDFT-CI combines the low-energy valence isomers to identify the most probable electronic configurations. By systematically varying oxidation states, spin states, and ligand identities, these computational methods reveal the spin coupling and effective charge on Fe active sites. CDFT-CI refines these insights by incorporating all relevant resonance forms to predict dominant chemical behavior. Together with experimental work from Prof. Dan Suess’s group, this computational approach provides critical insight into [FexSx] cluster behavior and supports the design of environmentally friendly, efficient catalysts for nitrogen fixation.
