Abstract
We report quantum chemical molecular dynamics (MD) simulations based on the density-functional tight-binding (DFTB) method to investigate the effect of K+, Na+, and Mg2+ ions in aqueous solutions on the static and dynamic structure of bulk water at room temperature and with various concentrations. The DFTB/MD simulations were validated for the description of ion solvation in aqueous ionic solutions by comparing static pair distribution functions (PDFs) as well as the cation solvation shell between experimental and available ab initio DFT data. The effect of the cations on the water structure, as well as relative differences between K+, Na+, and Mg2+ cations, were analyzed in terms of atomically resolved PDFs as well as time-dependent Van Hove correlation functions (VHFs). The investigation of the VHFs reveals that salt ions generally slow down the dynamic decay of the pair correlations in the water solvation sphere, irrespective of the cation size or charge.
| Original language | English |
|---|---|
| Pages (from-to) | 25500-25510 |
| Number of pages | 11 |
| Journal | RSC Advances |
| Volume | 12 |
| Issue number | 39 |
| DOIs | |
| State | Published - Sep 16 2022 |
Funding
We would like to thank Dr Ray A. Matsumoto and Prof. Peter T. Cummings of Vanderbilt University, Nashville, TN, for discussions on the generation of the Van Hove function. The authors acknowledge support by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. DOE Office of Science. The research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. This research made use of the resources at the High-Performance Computing Center at Idaho National Laboratory, which is supported by the Office of Nuclear Energy of the U.S. Dept. of Energy under Contract No. DE-AC07-05ID14517.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | DE-AC07-05ID14517 |
| Office of Science | DE-AC02-05CH11231 |
| Office of Nuclear Energy |