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Title: Nuclear quantum effects in water exchange around lithium and fluoride ions

Abstract

We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the water exchange reactions are unaffected by quantization, so a classical description of these reactions gives qualitatively correct and quantitatively reasonable results. We also find that the quantum effects in solutions of lithium are larger than in solutions of fluoride. This is partly due to the stronger interaction of lithium with water molecules, partly due tomore » the lighter mass of lithium, and partly due to competing quantum effects in the hydration of fluoride, which are absent in the hydration of lithium. LXD was supported by US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1184969
Report Number(s):
PNNL-SA-107037
KC0301020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics, 142(6):Article No. 064509
Country of Publication:
United States
Language:
English

Citation Formats

Wilkins, David M., Manolopoulos, David, and Dang, Liem X. Nuclear quantum effects in water exchange around lithium and fluoride ions. United States: N. p., 2015. Web. doi:10.1063/1.4907554.
Wilkins, David M., Manolopoulos, David, & Dang, Liem X. Nuclear quantum effects in water exchange around lithium and fluoride ions. United States. doi:10.1063/1.4907554.
Wilkins, David M., Manolopoulos, David, and Dang, Liem X. Sat . "Nuclear quantum effects in water exchange around lithium and fluoride ions". United States. doi:10.1063/1.4907554.
@article{osti_1184969,
title = {Nuclear quantum effects in water exchange around lithium and fluoride ions},
author = {Wilkins, David M. and Manolopoulos, David and Dang, Liem X.},
abstractNote = {We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the water exchange reactions are unaffected by quantization, so a classical description of these reactions gives qualitatively correct and quantitatively reasonable results. We also find that the quantum effects in solutions of lithium are larger than in solutions of fluoride. This is partly due to the stronger interaction of lithium with water molecules, partly due to the lighter mass of lithium, and partly due to competing quantum effects in the hydration of fluoride, which are absent in the hydration of lithium. LXD was supported by US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.},
doi = {10.1063/1.4907554},
journal = {Journal of Chemical Physics, 142(6):Article No. 064509},
number = ,
volume = ,
place = {United States},
year = {Sat Feb 14 00:00:00 EST 2015},
month = {Sat Feb 14 00:00:00 EST 2015}
}