Water Exchange Rates and Molecular Mechanism around Aqueous Halide Ions

Journal Article · Thu Jul 17 00:00:00 EDT 2014 · Journal of Physical Chemistry B, 118(28):7886-7891

DOI:https://doi.org/10.1021/jp500402j· OSTI ID:1171280

Annapureddy, Harsha V.; Dang, Liem X.

Molecular dynamics simulations were performed to systematically study the water-exchange mechanism around aqueous chloride, bromide, and iodide ions. Transition state theory, Grote-Hynes theory, and the reactive flux method were employed to compute water exchange rates. We computed the pressure dependence of rate constants and the corresponding activation volumes to investigate the mechanism of the solvent exchange event. The activation volumes obtained using the transition state theory rate constants are negative for all the three anions, thus indicating an associative mechanism. Contrary to the transition state theory results, activation volumes obtained using rate constants from Grote-Hynes theory and the reactive flux method are positive, thus indicating a dissociative mechanism. The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences (BES), of the U.S. Department of Energy (DOE) funded this work. Battelle operates Pacific Northwest National Laboratory for DOE. The calculations were carried out using computer resources provided by BES.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1171280
• Report Number(s): PNNL-SA-100320; KC0301020
• Journal Information: Journal of Physical Chemistry B, 118(28):7886-7891, Journal Name: Journal of Physical Chemistry B, 118(28):7886-7891
• Country of Publication: United States
• Language: English