An ab initio quantum mechanical charge field molecular dynamics simulation of a dilute aqueous HCl solution |
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| Authors: | Chinapong Kritayakornupong Viwat Vchirawongkwin Bernd M Rode |
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| Institution: | 1. Faculty of Science, Department of Chemistry, King Mongkut's University of Technology, Thonburi, Bangkok 10140, Thailand;2. Faculty of Science, Department of Chemistry, Chulalongkorn University, Bangkok 10330, Thailand;3. Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 52a, Innsbruck A‐6020, Austria |
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| Abstract: | An ab initio quantum mechanical charge field (QMCF) molecular dynamics simulation has been performed to study the structural and dynamical properties of a dilute aqueous HCl solution. The solute molecule HCl and its surrounding water molecules were treated at Hartree‐Fock level in conjunction with Dunning double‐ζ plus polarization function basis sets. The simulation predicts an average H? Cl bond distance of 1.28 Å, which is in good agreement with the experimental value. The HHCl···Ow and ClHCl···Hw distances of 1.84 and 3.51 Å were found for the first hydration shell. At the hydrogen site of HCl, a single water molecule is the most preferred coordination, whereas an average coordination number of 12 water molecules of the full first shell was observed for the chloride site. The hydrogen bonding at the hydrogen site of HCl is weakened by proton transfer reactions and an associated lability of ligand binding. Two proton transfer processes were observed in the QMCF MD simulation, demonstrating acid dissociation of HCl. A weak structure‐making/breaking effect of HCl in water is recognized from the mean residence times of 2.1 and 0.8 ps for ligands in the neighborhood of Cl and H sites of HCl, respectively. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 |
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| Keywords: | hydrogen chloride hydration structure dynamical properties hydrogen bond acid dissociation proton transfer simulation QMCF |
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