Mechanistic Insight into the Reaction of Organic Acids with SO3 at the Air–Water Interface

Jie Zhong, Hao Li, Manoj Kumar, Jiarong Liu, Ling Liu, Xiuhui Zhang, Xiao Cheng Zeng, Joseph S. Francisco

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


The gas-phase reaction of organic acids with SO3 has been recognized as essential in promoting aerosol-particle formation. However, at the air–water interface, this reaction is much less understood. We performed systematic Born–Oppenheimer molecular dynamics (BOMD) simulations to study the reaction of various organic acids with SO3 on a water droplet. The results show that with the involvement of interfacial water molecules, organic acids can react with SO3 and form the ion pair of sulfuric-carboxylic anhydride and hydronium. This mechanism is in contrast to the gas-phase reaction mechanisms in which the organic acid either serves as a catalyst for the reaction between SO3 and H2O or reacts with SO3 directly. The distinct reaction at the water surface has important atmospheric implications, for example, promoting water condensation, uptaking atmospheric condesation species, and incorporating “SO42−” into organic species in aerosol particles. Therefore, this reaction, typically occurring within a few picoseconds, provides another pathway towards aerosol formation.

Original languageEnglish (US)
Pages (from-to)8351-8355
Number of pages5
JournalAngewandte Chemie - International Edition
Issue number25
StatePublished - Jun 17 2019


  • SO
  • aerosols
  • air–water interface
  • molecular dynamics
  • organic acids

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry


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