Publication
Perfluorooctanoic Acid Monohydrate (PFOA-H2O) Studied by Molecular Rotational Resonance (MRR) Spectroscopy
Originally published in Chemical Physics Letters, April 2026
Authors: Ramya Gollamudi; Ailinh A. Tran; Heena S. Karani; Ybinh C. Tran; Sylvestre Twagirayezu; Justin L. Neill
Publication Summary
Originally published in Chemical Physics Letters, this study uses molecular rotational resonance (MRR) spectroscopy to investigate the structure of perfluorooctanoic acid monohydrate (PFOA-H₂O), a hydrated complex of the widely studied per-and polyfluoroalkyl substance (PFAS) compound PFOA. Using a broadband MRR spectrometer operating in the 2-8 GHz range, the researchers recorded and analyzed the rotational spectrum of PFOA-H₂O, revealing well-resolved spectral features from both the isolated molecule and its hydrated complex.
With the aid of quantum chemical calculations, the team assigned hundreds of rotational transitions and determined key molecular parameters, including rotational constants, dipole moment orientations, and characteristic rotational energy level patterns. The analysis revealed key structural features of PFOA-H₂O, including its preferred molecular conformation and interactions with water. The results provide new insight into the structural behavior of hydrated PFAS molecules and demonstrate the value of MRR spectroscopy for studying environmentally relevant contaminants at the molecular level.
Key Takeaways
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Investigates the structure of perfluorooctanoic acid monohydrate (PFOA-H₂O) using MRR spectroscopy.
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Records the rotational spectrum of PFOA-H₂O with a broadband MRR spectrometer operating from 2-8 GHz.
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Assigns more than 300 rotational transitions using spectroscopic analysis and quantum chemical calculations.
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Determines rotational constants, dipole moment orientations, and characteristic rotational energy level patterns.
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Reveals a helical PFOA-H₂O structure stabilized by fluorine-fluorine separation and weak hydrogen bonding.
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Demonstrates the utility of MRR spectroscopy for studying the structure and hydration of environmentally relevant PFAS compounds