Autoionization in Liquid Water

  title={Autoionization in Liquid Water},
  author={Philip L. Geissler and Christoph Dellago and David W. Chandler and J{\"u}rg Hutter and Michele Parrinello},
  pages={2121 - 2124}
The dissociation of a water molecule in liquid water is the fundamental event in acid-base chemistry, determining the pH of water. Because of the short time scales and microscopic length scales involved, the dynamics of this autoionization have not been directly probed by experiment. Here, the autoionization mechanism is revealed by sampling and analyzing ab initio molecular dynamics trajectories. We identify the rare fluctuations in solvation energies that destabilize an oxygen-hydrogen bond… 
On the recombination of hydronium and hydroxide ions in water
The mechanism of recombination in liquid water is elucidated with ab initio molecular dynamics simulations, and it emerges as quite different from the conventional view of the Grotthuss mechanism.
Observation of a Zundel-like transition state during proton transfer in aqueous hydroxide solutions
Calculations based on the EVB-MD model argue that the collective electric field in the proton transfer direction is the appropriate coordinate to describe the creation and relaxation of these Zundel-like transition states.
Local initiation conditions for water autoionization
This work investigated the self-ionization of water at room temperature by rare-event ab initio molecular dynamics and obtained autoionization rates and activation energies in good agreement with experiments and identified anomalies in the water structure that act as initiators of the reaction.
Reactions associated with ionization in water: a direct ab initio dynamics study of ionization in (H2O)17.
Quasiclassical ab initio simulations of the ionization dynamics in a (H(2)O)(17) cluster, the first water cluster that includes a fourfold coordinated (internally solvated) water molecule, have been
Special Pairs Are Decisive in the Autoionization and Recombination of Water.
A self-consistent picture of both processes based on the occurrence and role of ultrashort hydrogen bonds is developed, which points to a role for density fluctuations in autoionization events and in neutralization.
Water self-dissociation under the microscope: the Kw in confinement
Nanoconfinement has been shown to drastically affect the physical properties of water. Its effects on reactivity and dissociation, however, remain controversial, despite their importance to
Dissociation of nitric acid at an aqueous surface: Large amplitude motions in the contact ion pair to solvent-separated ion pair conversion.
Large amplitude, microscopic level motions-such as the hydrogen-bonding coordination number changes around the proton-donating and -accepting species-which are key for the CIP --> SSIP PT conversion are focused on.
Structural aspects of the topological model of the hydrogen bond in water on auto-dissociation via proton transfer.
Molecular dynamics simulations were used to investigate the structure and lifetimes of hydrogen bonds and auto dissociation via proton transfer in bulk water using a reactive and dissociative all-atom potential, and asymmetric bonding at the sub-100 femtosecond timescale is observed.
Ab initio molecular dynamics study of proton mobility in liquid methanol
The transport of protons through aqueous, partially aqueous, or nonaqueous hydrogen-bonded media is a fundamental process in many biologically and technologically important systems. Liquid methanol
Rare event simulations reveal subtle key steps in aqueous silicate condensation.
A replica exchange transition interface sampling (RETIS) study combined with Born-Oppenheimer molecular dynamics (BOMD) is used to investigate the dynamics, thermodynamics and the mechanism of the


Analysis of the Dissociation of H2O in Water Using First-Principles Molecular Dynamics
We have analyzed the structural, electronic, and dynamic properties along the reaction path of the dissociation of an H2O molecule in bulk water. There are four stages to the dissociation process,
Ab initio molecular dynamics simulation of the solvation and transport of hydronium and hydroxyl ions in water
Charge defects in water created by excess or missing protons appear in the form of solvated hydronium H3O+ and hydroxyl OH− ions. Using the method of ab initio molecular dynamics, we have
The computer simulation of proton transport in water
The dynamics and energetics of an excess proton in bulk phase water are examined computationally with a special emphasis on a quantum-dynamical treatment of the nuclear motion. The potential model
Transport and spectroscopy of the hydrated proton: A molecular dynamics study
In order to study the microscopic nature of the hydrated proton and its transport mechanism, we have introduced a multi-state empirical valence bond model, fitted to ab-initio results [J. Phys. Chem.
The dissociation mechanism of H2O in water studied by first-principles molecular dynamics
Abstract We have performed a series of Car–Parrinello simulations to investigate the dissociation of H 2 O in water. An intramolecular O–H bond length was chosen as the reaction coordinate and its
Ab initio analysis of proton transfer dynamics in (H2O)3H
Abstract We have harvested ab initio trajectories of proton transfer in (H 2 O) 3 H + by combining Car–Parrinello molecular dynamics (CPMD) with the transition path sampling method. Two transition
Role of nuclear tunneling in aqueous ferrous–ferric electron transfer
By computer simulation and also by analytical methods we have computed the nuclear tunneling enhancement of the rate for ferrous–ferric exchange in water. The model we have examined is the one
Photoinduction of Fast, Reversible Translational Motion in a Hydrogen-Bonded Molecular Shuttle
A rotaxane is described in which a macrocycle moves reversibly between two hydrogen-bonding stations after a nanosecond laser pulse and has properties characteristic of an energy-driven piston.
Ab initio molecular dynamics simulation of liquid water: Comparison of three gradient‐corrected density functionals
Three frequently used gradient‐corrected density functionals (B, BP, and BLYP) are applied in an ab initio molecular dynamics simulation of liquid water in order to evaluate their performance for the
On the Theory of Oxidation‐Reduction Reactions Involving Electron Transfer. I
A mechanism for electron transfer reactions is described, in which there is very little spatial overlap of the electronic orbitals of the two reacting molecules in the activated complex. Assuming