TY - JOUR

T1 - Temperature and concentration effects on Li+-ion hydration. A molecular dynamics simulation study

AU - Egorov, Andrey

AU - Komolkin, A. V.

AU - Chizhik, V. I.

AU - Yushmanov, P. V.

AU - Lyubartsev, A. P.

AU - Laaksonen, Aatto

PY - 2003/4/10

Y1 - 2003/4/10

N2 - Molecular dynamics simulations of aqueous LiCl solution have been carried out over wide concentration (from 0.1 to 11.4 mol/kg) and temperature (from -30 to 110 °C) ranges. Three different interaction potentials are investigated: the recent Li--water effective pair potential, derived from ab initio molecular dynamics simulations [Lyubartsev, A. P.; Laasonen, K.; Laaksonen, A. J. Chem. Phys. 2001, 114, 3120], as well as earlier potentials of Lennard-Jones type with two widely different sets of parameters [Dang, L. X.; J. Chem. Phys. 1992, 96, 6970 and Heinzinger, K.; Physica B 1985, 131, 196]. Hydration structure and residence times around Li+ are studied with focus on the still somewhat controversial issue of hydration structure: both tetrahedral and octahedral water coordination have been predicted from the experiments. Besides classical MD simulations, even complementary Car-Parrinello simulations were employed to investigate the stability of a possible six-coordinated hydration shell around lithium. Self-diffusion coefficients for lithium were calculated for Li+ from the simulations and compared to NMR spin - echo measurements. The new ab initio-based exponential Li+-H2O interaction potential appears to be robust giving the overall characteristic hydration properties in agreement with experiments. However, while it reproduces the radial distribution function (RDF) features from a recent neutron diffraction with isotopic substitution (NDIS) experiments with a well-pronounced tetrahedral water structure, the same experiment is interpreted to give octahedral water structure around lithium at the same concentrations and temperatures as were used in our simulations.

AB - Molecular dynamics simulations of aqueous LiCl solution have been carried out over wide concentration (from 0.1 to 11.4 mol/kg) and temperature (from -30 to 110 °C) ranges. Three different interaction potentials are investigated: the recent Li--water effective pair potential, derived from ab initio molecular dynamics simulations [Lyubartsev, A. P.; Laasonen, K.; Laaksonen, A. J. Chem. Phys. 2001, 114, 3120], as well as earlier potentials of Lennard-Jones type with two widely different sets of parameters [Dang, L. X.; J. Chem. Phys. 1992, 96, 6970 and Heinzinger, K.; Physica B 1985, 131, 196]. Hydration structure and residence times around Li+ are studied with focus on the still somewhat controversial issue of hydration structure: both tetrahedral and octahedral water coordination have been predicted from the experiments. Besides classical MD simulations, even complementary Car-Parrinello simulations were employed to investigate the stability of a possible six-coordinated hydration shell around lithium. Self-diffusion coefficients for lithium were calculated for Li+ from the simulations and compared to NMR spin - echo measurements. The new ab initio-based exponential Li+-H2O interaction potential appears to be robust giving the overall characteristic hydration properties in agreement with experiments. However, while it reproduces the radial distribution function (RDF) features from a recent neutron diffraction with isotopic substitution (NDIS) experiments with a well-pronounced tetrahedral water structure, the same experiment is interpreted to give octahedral water structure around lithium at the same concentrations and temperatures as were used in our simulations.

UR - http://www.scopus.com/inward/record.url?scp=0037431226&partnerID=8YFLogxK

U2 - 10.1021/jp026677l

DO - 10.1021/jp026677l

M3 - Article

AN - SCOPUS:0037431226

VL - 107

SP - 3234

EP - 3242

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 14

ER -