Polarization and charge transfer in the hydration of chloride ions
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221-0172 (United States)
- Department of Chemistry and Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221-0172 (United States)
A theoretical study of the structural and electronic properties of the chloride ion and water molecules in the first hydration shell is presented. The calculations are performed on an ensemble of configurations obtained from molecular dynamics simulations of a single chloride ion in bulk water. The simulations utilize the polarizable AMOEBA force field for trajectory generation and MP2-level calculations are performed to examine the electronic structure properties of the ions and surrounding waters in the external field of more distant waters. The ChelpG method is employed to explore the effective charges and dipoles on the chloride ions and first-shell waters. The quantum theory of atoms in molecules (QTAIM) is further utilized to examine charge transfer from the anion to surrounding water molecules. The clusters extracted from the AMOEBA simulations exhibit high probabilities of anisotropic solvation for chloride ions in bulk water. From the QTAIM analysis, 0.2 elementary charges are transferred from the ion to the first-shell water molecules. The default AMOEBA model overestimates the average dipole moment magnitude of the ion compared to the quantum mechanical value. The average magnitude of the dipole moment of the water molecules in the first shell treated at the MP2-level, with the more distant waters handled with an AMOEBA effective charge model, is 2.67 D. This value is close to the AMOEBA result for first-shell waters (2.72 D) and is slightly reduced from the bulk AMOEBA value (2.78 D). The magnitude of the dipole moment of the water molecules in the first solvation shell is most strongly affected by the local water-water interactions and hydrogen bonds with the second solvation shell, rather than by interactions with the ion.
- OSTI ID:
- 21559871
- Journal Information:
- Journal of Chemical Physics, Vol. 132, Issue 1; Other Information: DOI: 10.1063/1.3283900; (c) 2010 American Institute of Physics; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANIONS
ANISOTROPY
CHARGE EXCHANGE
CHLORINE COMPOUNDS
CHLORINE IONS
DIPOLE MOMENTS
DIPOLES
EFFECTIVE CHARGE
ELECTRONIC STRUCTURE
HYDRATION
HYDROGEN
INTERACTIONS
LIQUIDS
MOLECULAR DYNAMICS METHOD
MOLECULES
POLARIZATION
QUANTUM MECHANICS
SIMULATION
WATER
CALCULATION METHODS
CHARGED PARTICLES
ELEMENTS
FLUIDS
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
IONS
MECHANICS
MULTIPOLES
NONMETALS
OXYGEN COMPOUNDS
SOLVATION