Toward the Mechanism of Ionic Dissociation in Water

Autor(en)

Andrew J. Ballard, Christoph Dellago

Abstrakt

We investigate the solvent effects leading to dissociation of sodium chloride in water. Thermodynamic analysis reveals dissociation to be driven energetically and opposed entropically, with the loss in entropy due to an increasing number of solvent. molecules entering the highly coordinated ionic solvation shell. We show through Committor analysis that the ion-ion distance is an insufficient reaction coordinate; in agreement with previous findings. By application of committor analysis on various constrained solvent ensembles, we find that the dissociation event is generally sensitive to solvent fluctuations at long ranges, with both sterics and electrostatics of importance. The dynamics of the reaction reveal that solvent rearrangements leading to dissociation occur on time scales from 0.5 to 5 ps or longer, and that, near the transition state, inertial effects enhance the reaction probability of a given trajectory.

Organisation(en)

Computergestützte Physik und Physik der Weichen Materie

Externe Organisation(en)

University of Maryland, College Park

Journal

The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical

Band

116

Seiten

13490-13497

Anzahl der Seiten

8

ISSN

1520-6106

DOI

https://doi.org/10.1021/jp309300b

Publikationsdatum

2012

Peer-reviewed

Ja

ÖFOS 2012

103036 Theoretische Physik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/ed75e9a1-bb72-4018-90d0-f032156bcb15