Dependence of the rate of LiF ion pairing on the description of molecular interaction

Journal Article · Thu Mar 03 00:00:00 EST 2016 · Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

DOI:https://doi.org/10.1021/acs.jpcb.5b09344· OSTI ID:1254580

Pluharova, Eva; Baer, Marcel D.; Schenter, Gregory K.; Jungwirth, Pavel; Mundy, Christopher J.

We present an analysis of the dynamics of ion-pairing of Lithium Fluoride (LiF) in aqueous solvent using both detailed molecular simulation as well as reduced models within a Gener- alized Langevin Equation (GLE) framework. We explored the sensitivity of the ion-pairing phenomena to the details of descriptions of molecular interaction, comparing two empirical potentials to explicit quantum based density functional theory. We find quantitative differences in the potentials of mean force for ion-pairing as well as time dependent frictions that lead to variations in the rate constant and reactive flux correlation functions. These details reflect differences in solvent response to ion-pairing between different representations of molecular interaction and influence anharmonicity of the dynamic response. We find that the short time anharmonic response is recovered with a GLE parameterization. Recovery of the details of long time response may require extensions to the reduced model. We show that the utility of using a reduced model leads to a straight forward application of variational transition state the- ory concepts to the condensed phase system. The significance of this is reflected in the analysis of committor distributions and the variation of planar hypersurfaces, leading to an improved understanding of factors that determine the rate of LiF ion-pairing. CJM and GKS are supported by the U.S. Department of Energy‘s (DOE) Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest Na- tional Laboratory (PNNL) is operated for the Department of Energy by Battelle. MDB is grateful for the support of Laboratory Directed Research and Development funding under the auspices of PNNL’s Laboratory Initiative Materials Synthesis and Simulation across Scales (MS3). Additional computing resources were generously allocated by PNNL’s Institutional Computing program. EP acknowledges support from PNNL’s Alternate Sponsored Fellowship program and IMPRS Dres- den.Support to P.J. from the Czech Science Foundation (grant P208/12/G016) and the Academy of Sciences (Praemium Academie award) is gratefully acknowledged.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1254580
• Report Number(s): PNNL-SA-113233; KC0301050
• Journal Information: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Vol. 120, Issue 8; ISSN 1520-6106
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English