Velocity auto-correlation function of ions and water molecules in different concentrations, anions and ion clusters

Katsufumi Tomobe, Eiji Yamamoto, Dusan Kojic, Masato Yasui, Kenji Yasuoka

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The characteristics of ion solvation are important for electrochemical and biophysical phenomena because all such phenomena occur under the presence of solvated ions. In this study, we performed an all-atom molecular dynamics simulation of aqueous NaCl ranging from 0.5 to 3.0 M, and aqueous NaF, NaBr and NaI in 2.0 M, to investigate the time-averaged velocity auto-correlation function (TAVAF) of ions and water molecules. By comparing the concentrations and ion pairs, we observed three behaviours: (i) in the case of NaCl, the velocity auto-correlation of Cl- becomes weaker as the concentration increases, whereas those of Na+ are not clearly different, (ii) the intensity of fluctuations of the TAVAF gradually decreases following the decrease in ionic radius and (iii) every TAVAF of water molecules in ionic solutions is clearly lower than that of bulk because of the cage effect. Furthermore, we observed that the first minimum of the TAVAF in the cluster is smaller than that of the isolated ions. These results indicate that the diffusion of ions and water molecules is affected by cage effect, and that the generation of ion cluster affects the diffusion of ions.

Original languageEnglish
Pages (from-to)840-844
Number of pages5
JournalMolecular Simulation
Issue number10-12
Publication statusPublished - 2015 Aug 13


  • ion cluster
  • ion solution
  • molecular dynamics simulation
  • velocity auto-correlation

ASJC Scopus subject areas

  • Chemistry(all)
  • Information Systems
  • Chemical Engineering(all)
  • Modelling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics


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