Abstract
The ability to reproduce the experimental structure of water around the sodium and potassium ions is a key test of the quality of interaction potentials due to the central importance of these ions in a wide range of important phenomena. Here, we simulate the Na+ and K+ ions in bulk water using three density functional theory functionals: (1) the generalized gradient approximation (GGA) based dispersion corrected revised Perdew, Burke, and Ernzerhof functional (revPBE-D3) (2) the recently developed strongly constrained and appropriately normed (SCAN) functional (3) the random phase approximation (RPA) functional for potassium. We compare with experimental X-ray diffraction (XRD) and X-ray absorption fine structure (EXAFS) measurements to demonstrate that SCAN accurately reproduces key structural details of the hydration structure around the sodium and potassium cations, whereas revPBE-D3 fails to do so. However, we show that SCAN provides a worse description of pure water in comparison with revPBE-D3. RPA also shows an improvement for K+, but slow convergence prevents rigorous comparison. Finally, we analyse cluster energetics to show SCAN and RPA have smaller fluctuations of the mean error of ion-water cluster binding energies compared with revPBE-D3.
| Original language | English |
|---|---|
| Pages (from-to) | 10641-10652 |
| Number of pages | 12 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 22 |
| Issue number | 19 |
| DOIs | |
| State | Published - May 21 2020 |
Funding
TTD, MG, GKS and CJM were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. MD Baer was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative, a Laboratory Directed Research and Development Program PNNL. PNNL is a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy. The RPA and SCAN calculation 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. Calculations were also performed on PNNL\u2019s Institutional Computing resource. The Na XAFS measurements were performed at the PHOENIX beamline of the Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland. JW and JH are supported by The National Centre of Competence in Research (NCCR) Materials Revolution: Computational Design and Discovery of Novel Materials (MARVEL) of the Swiss National Science Foundation (SNSF). XSZ and TTD acknowledge the Australian Research Council (ARC) funding via project number FL170100101. MDB is supported by the Center for Computational Study of Excited-State Phenomena in Energy Materials (C2SEPEM) and by the SciDAC Program on Excited State Phenomena in Energy Materials at the Lawrence Berkeley National Laboratory, which is funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-05CH11231, as part of the Computational Materials Sciences Program. This research used resources of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory and was supported under DOE under Contract No. DE-AC02-06CH11357, and the Canadian Light Source and its funding partners. This research was undertaken with the assistance of resources from QCIF (http://www.qcif.edu.au).