A multistate empirical valence bond model for solvation and transport simulations of OH- in aqueous solutions

Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Physical Chemistry Chemical Physics (Impact Factor: 4.49). 11/2009; 11(41):9420-30. DOI: 10.1039/b907859b
Source: PubMed


We describe a new multistate empirical valence bond (MS-EVB) model of OH(-) in aqueous solutions. This model is based on the recently proposed "charged ring" parameterization for the intermolecular interaction of hydroxyl ion with water [Ufimtsev, et al., Chem. Phys. Lett., 2007, 442, 128] and is suitable for classical molecular simulations of OH(-) solvation and transport. The model reproduces the hydration structure of OH(-)(aq) in good agreement with experimental data and the results of ab initio molecular dynamics simulations. It also accurately captures the major structural, energetic, and dynamic aspects of the proton transfer processes involving OH(-) (aq). The model predicts an approximately two-fold increase of the OH(-) mobility due to proton exchange reactions.

Full-text preview

Available from:
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A scientific review informed about the anomalous diffusion of hydroxide in basic solutions OH-. The discussion was initiated with a review of structural diffusion of H+ in acidic solutions, enabling a comparison to be made. The presentation was based on the formal and unifying 'presolvation concept' that was explained within the context of the H+ diffusion process. A theoretical formalism was used by the researchers to connect the qualitative predictions of the presolvation concept to actual mechanisms and the resulting kinetics in quantitative detail. The theoretical formalism allowed structural diffusion to be analyzed on the basis of appropriately defined population correlation functions. This theoretical framework led to consistent sets of various lifetimes and rates for OH- that were directly compared to H+.
    Chemical Reviews 02/2010; 110(4):2174-216. DOI:10.1021/cr900233f · 46.57 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Fuel cells are an attractive alternative to other energy conversion methods because of their efficiency and energy density. Unfortunately, the high expense and limited durability of catalysts in common fuel cells has slowed their commercialization. The limitations of current anion exchange membranes (AEMs) may be minimized by improved design and material optimization. This work aims to improve the understanding of fuel cell AEMs from a fundamental perspective through multiscale simulation techniques. Studies on hydroxide anions in relevant AEMs reveal the importance of explicitly including the physics of proton shuttling to properly describe the solvation and transport of the ions in these systems. These results are in turn bridged to a mesoscopic simulation methodology that incorporates the morphological features of the membrane, leading to a better understanding of the coupling of domain structure to charge transport processes and its affect on ion conductance properties.
    220th ECS Meeting; 01/2011
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ab initio path integral molecular dynamics simulation of M(+)(H(3)O(2)(-)) (M = Li, Na, and K) has been carried out to analyze how the structure and dynamics of a low-barrier hydrogen-bonded Zundel anion, H(3)O(2)(-), can be affected by the counter alkali metal cation, M(+). Our simulation predicts that the quantum proton transfer in Zundel anion can be strongly coupled to the motion of counter cation located nearby. A smaller cation can induce larger structural distortion of the Zundel anion fragment making the proton transfer barrier higher, and hence, lower the vibrational excitation energy. It is also argued that a large H∕D isotope effect is present.
    The Journal of Chemical Physics 01/2011; 134(3):031101. DOI:10.1063/1.3544212 · 2.95 Impact Factor
Show more