Revisiting atmospheric sulfur chemistry: Acid-catalyzed pathways do not control H2SO4 formation
5 affiliations
- 1College of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, China
- 2College of Physics and Mechatronic Engineering, Guizhou Minzu University, Guiyang 550025, China
- 3Department of Earth and Environmental Sciences, University of Pennsylvania, Philadelphia, PA 19104
- 4Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
- 5Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431
Abstract
Sulfuric acid (H₂SO4) drives new particle formation and radiatively important aerosol processes in the atmosphere, but its formation pathways remain poorly resolved because of limited kinetics data. To clarify these pathways, we combined coupled-cluster calculations, reaction rate theory, and a global chemistry transport model to quantify acid-catalyzed SO3 hydration and its atmospheric significance. We find that the overall kinetics is not governed by a tight transition state but rather is controlled by a preceding loose transition state associated with the formation of the precursor complex of the acid-catalyzed SO3 hydration. Our results reverse a recent view that acid catalysis is the dominant contributor to atmospheric SO3 hydration, instead supporting an earlier view that water catalysis dominates SO3 hydration. Incorporating the revised kinetics into the GEOS-Chem atmospheric model reveals no significant impact of acid-catalyzed SO3 hydration on the simulated concentrations of H2SO4. The present findings highlight the critical roles of variational transition states in kinetic modeling.
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BibTeX
@article{long2026revisiting,
title = {{Revisiting atmospheric sulfur chemistry: Acid-catalyzed pathways do not control H2SO4 formation}},
author = {Bo Long and Chaolu Xie and Joseph S. Francisco and Donald G. Truhlar},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
year = {2026},
month = oct,
doi = {10.1073/pnas.2612824123},
url = {https://doi.org/10.1073/pnas.2612824123},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Revisiting atmospheric sulfur chemistry: Acid-catalyzed pathways do not control H2SO4 formation
AU - Bo Long
AU - Chaolu Xie
AU - Joseph S. Francisco
AU - Donald G. Truhlar
PY - 2026
DA - 2026/10/27
JO - Proceedings of the National Academy of Sciences of the United States of America
DO - 10.1073/pnas.2612824123
UR - https://doi.org/10.1073/pnas.2612824123
AB - Sulfuric acid (H₂SO4) drives new particle formation and radiatively important aerosol processes in the atmosphere, but its formation pathways remain poorly resolved because of limited kinetics data. To clarify these pathways, we combined coupled-cluster calculations, reaction rate theory, and a global chemistry transport model to quantify acid-catalyzed SO3 hydration and its atmospheric significance. We find that the overall kinetics is not governed by a tight transition state but rather is controlled by a preceding loose transition state associated with the formation of the precursor complex of the acid-catalyzed SO3 hydration. Our results reverse a recent view that acid catalysis is the dominant contributor to atmospheric SO3 hydration, instead supporting an earlier view that water catalysis dominates SO3 hydration. Incorporating the revised kinetics into the GEOS-Chem atmospheric model reveals no significant impact of acid-catalyzed SO3 hydration on the simulated concentrations of H2SO4. The present findings highlight the critical roles of variational transition states in kinetic modeling.
SN - 0027-8424
SN - 1091-6490
ER -