Structure and dynamics of aqueous solutions of electrolytes in confined space

Yoshimasa Yamakawa, Masakazu Matsumoto, Hideki Tanaka

Research output: Contribution to journalArticle

Abstract

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
Volume81
Issue numberSUPPL. A
Publication statusPublished - Sep 2012

Fingerprint

electrolytes
tubes
aqueous solutions
ions
dehydration
hydration
potassium
diffusion coefficient
relaxation time
chlorides
molecular dynamics
configurations
simulation

Keywords

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

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Structure and dynamics of aqueous solutions of electrolytes in confined space. / Yamakawa, Yoshimasa; Matsumoto, Masakazu; Tanaka, Hideki.

In: Journal of the Physical Society of Japan, Vol. 81, No. SUPPL. A, SA025, 09.2012.

Research output: Contribution to journalArticle

@article{483bb0090e094819b7c18fee100d455a,
title = "Structure and dynamics of aqueous solutions of electrolytes in confined space",
abstract = "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.",
keywords = "Aqueous solution, Ion channel, Molecular dynamics simulation, Tubule space",
author = "Yoshimasa Yamakawa and Masakazu Matsumoto and Hideki Tanaka",
year = "2012",
month = "9",
language = "English",
volume = "81",
journal = "Journal of the Physical Society of Japan",
issn = "0031-9015",
publisher = "Physical Society of Japan",
number = "SUPPL. A",

}

TY - JOUR

T1 - Structure and dynamics of aqueous solutions of electrolytes in confined space

AU - Yamakawa, Yoshimasa

AU - Matsumoto, Masakazu

AU - Tanaka, Hideki

PY - 2012/9

Y1 - 2012/9

N2 - 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.

AB - 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.

KW - Aqueous solution

KW - Ion channel

KW - Molecular dynamics simulation

KW - Tubule space

UR - http://www.scopus.com/inward/record.url?scp=84866410308&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84866410308&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:84866410308

VL - 81

JO - Journal of the Physical Society of Japan

JF - Journal of the Physical Society of Japan

SN - 0031-9015

IS - SUPPL. A

M1 - SA025

ER -