Molecular dynamics simulations of the evaporation of hydrated ions from aqueous solution

Philip Loche, Douwe J. Bonthuis, Roland R. Netz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Although important for atmospheric processes and gas-phase catalysis, very little is known about the hydration state of ions in the vapor phase. Here we study the evaporation energetics and kinetics of a chloride ion from liquid water by molecular dynamics simulations. As chloride permeates the interface, a water finger forms and breaks at a chloride separation of ≈ 2.8 nm from the Gibbs dividing surface. For larger separations from the interface, about 7 water molecules are estimated to stay bound to chloride in saturated water vapor, as corroborated by continuum dielectrics and statistical mechanics models. This ion hydration significantly reduces the free-energy barrier for evaporation. The effective chloride diffusivity in the transition state is found to be about 6 times higher than in bulk, which reflects the highly mobile hydration dynamics as the water finger breaks. Both effects significantly increase the chloride evaporation flux from the quiescent interface of an electrolyte solution, which is predicted from reaction kinetic theory.

Original languageEnglish
Article number55
JournalCommunications Chemistry
Issue number1
Publication statusPublished - Dec 2022

ASJC Scopus subject areas

  • Biochemistry
  • Chemistry(all)
  • Environmental Chemistry
  • Materials Chemistry


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