Role of solvation structure in the shuttling of the hydrated excess proton
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The classic Marcus electron transfer reaction model demonstrated that a barrierless electron transfer reaction can occur when both the reactant and product have almost similar solvation environment. In our recently developed proton model, we have incorporated the pre-solvation concept and showed that it indeed facilitates the proton diffusion in aqueous solution. In this work, we further quantify the degree of pre-solvation using different structural parameters, e.g., tetrahedral order parameter, average numbers of hydrogen bonds. All the above said parameters exhibit a very strong correlation with the proton share parameter. The more Zundel-like configurations have almost identical solvation environment for both the water molecules and support the pre-solvation concept. However, in the case of Eigen-like configurations, the central hydronium and “special pair” water have distinctly different solvation structures.
KeywordsEmpirical valence bond reactive molecular dynamics pre-solvation proton transfer proton transport
This research was supported in part by the Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences, and Biosciences, (DOE-BES Grant No. DE-SC0005418), and by the National Science Foundation (NSF Grant No. CHE-1465248). The computational resources in this work were provided by the University of Chicago Research Computing Center (RCC).
- 1.Decoursey T E 2003 Voltage-gated proton channels and other proton transfer pathways Physiol. Rev. 83 475Google Scholar
- 5.Kreuer K D, Paddison S J, Spohr E and Schuster M 2004 Transport in proton conductors for fuel-cell applications: Simulations, elementary reactions, and phenomenology Chem. Rev. 104 4637Google Scholar
- 10.Zundel G 2000 Hydrogen Bonds with Large Proton Polarizability and Proton Transfer Processes in Electrochemistry and Biology Adv. Chem. Phys. 111 1Google Scholar
- 11.von Grotthuss C J T 1806 Sur la décomposition de l’eau et des corps qu’elle tient en dissolution à l’aide de l’électricité galvanique Ann. Chim. 58 54Google Scholar
- 35.Marx D, Chandra A and Tuckerman M E 2010 Aqueous Basic Solutions: Hydroxide Solvation, Structural Diffusion, and Comparison to the Hydrated Proton Chem. Rev. 110 2174Google Scholar
- 45.Marx D and Hutter J 2009 In Ab Initio Molecular Dynamics: Basic Theory and Advanced Methods (New York: Cambridge University Press)Google Scholar
- 50.Ando K and Hynes J T 1999 Acid-Base Proton Transfer and Ion Pair Formation in Solution Adv. Chem. Phys. 110 381Google Scholar
- 51.All the terms in a diagonal element are described by the classical force fields, with the exception of the intermolecular term between hydronium and water in which contains two extra “repulsive terms”. See the original MS-EVB3 paperGoogle Scholar
- 56.Allen M P and Tildesley D J 1989 In Computer Simulation of Liquids (New York: Oxford University Press)Google Scholar
- 58.Chau P L and Hardwick A J 1998 A new order parameter for tetrahedral configurations Mol. Phys. 93 511Google Scholar