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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