Role of base strength, cluster structure and charge in sulfuric-acid-driven particle formation

Nanna Myllys, Jakub Kubecka, Vitus Besel, Dina Alfaouri, Tinja Olenius, James Norman Smith, Monica Passananti

Research output: Contribution to journalArticleScientificpeer-review

Abstract

In atmospheric sulfuric-acid-driven particle formation, bases are able to stabilize the initial molecular clusters and thus enhance particle formation. The enhancing potential of a stabilizing base is affected by different factors, such as the basicity and abundance. Here we use weak (ammonia), medium strong (dimethylamine) and very strong (guanidine) bases as representative atmospheric base compounds, and we systematically investigate their ability to stabilize sulfuric acid clusters. Using quantum chemistry, we study proton transfer as well as intermolecular interactions and symmetry in clusters, of which the former is directly related to the base strength and the latter to the structural effects. Based on the theoretical cluster stabilities and cluster population kinetics modeling, we provide molecular-level mechanisms of cluster growth and show that in electrically neutral particle formation, guanidine can dominate formation events even at relatively low concentrations. However, when ions are involved, charge effects can also stabilize small clusters for weaker bases. In this case the atmospheric abundance of the bases becomes more important, and thus ammonia is likely to play a key role. The theoretical findings are validated by cluster distribution experiments, as well as comparisons to previously reported particle formation rates, showing a good agreement.

Original languageEnglish
JournalAtmospheric Chemistry and Physics
Volume19
Issue number15
Pages (from-to)9753-9768
Number of pages16
ISSN1680-7324
DOIs
Publication statusPublished - 2 Aug 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences
  • GUANIDINO COMPOUNDS
  • NUCLEATION
  • GROWTH
  • DIMETHYLAMINE
  • AMMONIA
  • AMINES
  • NANOPARTICLES
  • METHYLAMINE
  • DIAMINES
  • IONS

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