Second-Generation ReaxFF Water Force Field: Improvements in the Description of Water Density and OH-Anion Diffusion

Weiwei Zhang, Adri C.T. Van Duin

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Hydronium (H3O+) and hydroxide (OH-) ions have anomalously large diffusion constants in aqueous solutions due to their combination of vehicular and Grotthuss hopping diffusion mechanisms. An improvement of the ReaxFF reactive water force field on the basis of our first-generation water force field (water-2010) is presented to describe the proton transfer (PT) mechanisms of H3O+ and OH- in water. Molecular dynamics simulation studies with the water-2017 force field support the Eigen-Zundel-Eigen mechanism for PT in acidic aqueous solution and reproduce the hypercoordinated solvation structure of the OH- in a basic environment. In particular, it predicts the correct order of the diffusion constants of H2O, H3O+, and OH- and their values are in agreement with the experimental data. Another interesting observation is that the diffusion constants of H3O+ and OH- are close to each other at high concentration due to the strong correlation between OH- ions in basic aqueous solution. On the basis of our results, it is shown that ReaxFF provides a novel approach to study the complex acid-base chemical reactions in aqueous solution with any pH value. (Chemical Equation Presented).

Original languageEnglish (US)
Pages (from-to)6021-6032
Number of pages12
JournalJournal of Physical Chemistry B
Volume121
Issue number24
DOIs
StatePublished - Jun 22 2017

All Science Journal Classification (ASJC) codes

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

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