Thermodynamics and Kinetics of Na+/K+-Formate Ion Pairs Association in Polarizable Water: A Molecular Dynamics Study

Journal Article · Mon Dec 03 00:00:00 EST 2012 · Chemical Physics Letters, 554:90-95

DOI:https://doi.org/10.1016/j.cplett.2012.10.049· OSTI ID:1059195

Nguyen, Phuong T; Nguyen, Van T; Annapureddy, Harsha V; Dang, Liem X; Do, Duong D

To elevate our understanding of ion specific activity in biological systems, the potential of mean force approach was utilized to study solvent effects on interactions between two alkali cations (Na+ and K+) with a formate anion in water. A very complex free energy landscape was observed, much more so than alkali-halide ion pairs. Furthermore, stronger binding between the Na+-formate pair was found in comparison to the K+-formate pair in water, a finding that agrees with experimental and theoretical studies of these systems. The kinetics of ion-pair interconversions were studied using transition rate theory, along with a variety of theoretical approaches such as the Kramers and Grote Hynes theories. These rate results were used to predict solvent effects on dynamical features of contact ion-pair association, in which faster dynamics were found for K+-formate pairs than for Na+-formate pairs. This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for DOE by Battelle.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1059195
• Report Number(s): PNNL-SA-90353; KC0301020
• Journal Information: Chemical Physics Letters, 554:90-95, Journal Name: Chemical Physics Letters, 554:90-95
• Country of Publication: United States
• Language: English