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Title: Real single ion solvation free energies with quantum mechanical simulation

Abstract

Single ion solvation free energies are one of the most important properties of electrolyte solutions and yet there is ongoing debate about what these values are. Only the values for neutral ion pairs are known. Here, we use DFT interaction potentials with molecular dynamics simulation (DFT-MD) combined with a modified version of the quasi-chemical theory (QCT) to calculate these energies for the lithium and fluoride ions. A method to correct for the error in the DFT functional is developed and very good agreement with the experimental value for the lithium fluoride pair is obtained. Moreover, this method partitions the energies into physically intuitive terms such as surface potential, cavity and charging energies which are amenable to descriptions with reduced models. Here, our research suggests that lithium's solvation free energy is dominated by the free energetics of a charged hard sphere, whereas fluoride exhibits significant quantum mechanical behavior that cannot be simply described with a reduced model.

Authors:
ORCiD logo [1];  [1];  [1];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1390418
Report Number(s):
PNNL-SA-123711
Journal ID: ISSN 2041-6520; CSHCBM; KC0301050
Grant/Contract Number:
AC05-76RL01830
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 8; Journal Issue: 9; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Duignan, Timothy T., Baer, Marcel D., Schenter, Gregory K., and Mundy, Christopher J.. Real single ion solvation free energies with quantum mechanical simulation. United States: N. p., 2017. Web. doi:10.1039/c7sc02138k.
Duignan, Timothy T., Baer, Marcel D., Schenter, Gregory K., & Mundy, Christopher J.. Real single ion solvation free energies with quantum mechanical simulation. United States. doi:10.1039/c7sc02138k.
Duignan, Timothy T., Baer, Marcel D., Schenter, Gregory K., and Mundy, Christopher J.. Tue . "Real single ion solvation free energies with quantum mechanical simulation". United States. doi:10.1039/c7sc02138k. https://www.osti.gov/servlets/purl/1390418.
@article{osti_1390418,
title = {Real single ion solvation free energies with quantum mechanical simulation},
author = {Duignan, Timothy T. and Baer, Marcel D. and Schenter, Gregory K. and Mundy, Christopher J.},
abstractNote = {Single ion solvation free energies are one of the most important properties of electrolyte solutions and yet there is ongoing debate about what these values are. Only the values for neutral ion pairs are known. Here, we use DFT interaction potentials with molecular dynamics simulation (DFT-MD) combined with a modified version of the quasi-chemical theory (QCT) to calculate these energies for the lithium and fluoride ions. A method to correct for the error in the DFT functional is developed and very good agreement with the experimental value for the lithium fluoride pair is obtained. Moreover, this method partitions the energies into physically intuitive terms such as surface potential, cavity and charging energies which are amenable to descriptions with reduced models. Here, our research suggests that lithium's solvation free energy is dominated by the free energetics of a charged hard sphere, whereas fluoride exhibits significant quantum mechanical behavior that cannot be simply described with a reduced model.},
doi = {10.1039/c7sc02138k},
journal = {Chemical Science},
number = 9,
volume = 8,
place = {United States},
year = {Tue Jul 04 00:00:00 EDT 2017},
month = {Tue Jul 04 00:00:00 EDT 2017}
}

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Cited by: 1 work
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