Lifetimes of excess protons in water using a dissociative water potential

Glenn K. Lockwood, Steve Garofalini

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Molecular dynamics simulations using a dissociative water potential were applied to study transport of excess protons in water and determine the applicability of this potential to describe such behavior. While originally developed for gas-phase molecules and bulk liquid water, the potential is transferrable to nanoconfinement and interface scenarios. Applied here, it shows proton behavior consistent with ab initio calculations and empirical models specifically designed to describe proton transport. Both Eigen and Zundel complexes are observed in the simulations showing the Eigen-Zundel-Eigen-type mechanism. In addition to reproducing the short-time rattling of the excess proton between the two oxygens of Zundel complexes, a picosecond-scale lifetime was also found. These longer-lived H3O+ ions are caused by the rapid conversion of the local solvation structure around the transferring proton from a Zundel-like form to an Eigen-like form following the transfer, effectively severing the path along which the proton can rattle. The migration of H+ over long times (>100 ps) deviates from the conventional short-time multiexponentially decaying lifetime autocorrelation model and follows the t-3/2 power-law behavior. The potential function employed here matches many of the features of proton transport observed in ab initio molecular dynamics simulations as well as the highly developed empirical valence bond models, yet is computationally very efficient, enabling longer time and larger systems to be studied.

Original languageEnglish
Pages (from-to)4089-4097
Number of pages9
JournalJournal of Physical Chemistry B
Volume117
Issue number15
DOIs
Publication statusPublished - Apr 18 2013

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Protons
life (durability)
protons
Water
water
Molecular dynamics
molecular dynamics
simulation
Solvation
Computer simulation
Autocorrelation
autocorrelation
solvation
Gases
Ions
vapor phases
Oxygen
valence
Hydrogen
Molecules

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Lifetimes of excess protons in water using a dissociative water potential. / Lockwood, Glenn K.; Garofalini, Steve.

In: Journal of Physical Chemistry B, Vol. 117, No. 15, 18.04.2013, p. 4089-4097.

Research output: Contribution to journalArticle

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