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. 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.

arXiv comment13 pages, 4 figures

References in corpus (9)

• Separable Dual Space Gaussian Pseudo-potentials
• Absolute Hydration Free Energies of Ions, Ion-Water Clusters, and Quasi-chemical Theory
• Molecular theories and simulation of ions and polar molecules in water
• Ab initio molecular dynamics calculations of ion hydration free energies
• Mass Density Fluctuations in Quantum and Classical descriptions of Liquid Water
• Quasi-Chemical and Structural Analysis of Polarizable Anion Hydration
• Nuclear quantum effects in water exchange around lithium and fluoride ions
• Thermodynamics of water modeled using ab initio simulations
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Cited by in corpus (10)

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• Quasi-Chemical Theory with Cluster Sampling from Ab Initio Molecular Dynamics: Fluoride (F${}^{-}$) Anion Hydration
• The Influence of Distant Boundaries on the Solvation of Charged Particles
• Quadrupole-mediated dielectric response and the charge-asymmetric solvation of ions in water
• Many-Body Quantum Muon Effects and Quadrupolar Coupling in Solids
• Response Theory for Static and Dynamic Solvation of Ionic and Dipolar Solutes in Water
• Distributed Charge Models of Liquid Methane and Ethane for Dielectric Effects and Solvation