Structure and dynamics of aqueous solutions of electrolytes in confined space

Yoshimasa Yamakawa, Masakazu Matsumoto, Hideki Tanaka

Research output: Contribution to journalArticlepeer-review


We perform isothermal-isobaric molecular dynamics simulations of aqueous solutions of potassium and chloride ions with varying tube diameter. An equilibrium state is attained within 1 ns, but the relaxation time to equilibrium is dependent on the initial arrangement of ions. When the tube diameter is larger than 1 nm, ions exchange their axial positions in few tens of picosecond to be the most stable configuration in which counterions are lined up alternately. However, ions in a tube narrower than 1 nm cannot exchange the mutual positions in axial-coordinate within an order of nano second. The axial self-diffusion coefficients are also examined. It is found that they increase with increasing the tube size once an equilibrium is attained. These results suggest the partial hydration and dehydration play a certain role in diffusion of the electrolytes in confined space like tubes and channels.

Original languageEnglish
Article numberSA025
Journaljournal of the physical society of japan
Issue numberSUPPL. A
Publication statusPublished - Sept 2012


  • Aqueous solution
  • Ion channel
  • Molecular dynamics simulation
  • Tubule space

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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