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Published July 28, 2018 | public
Journal Article

Density functional theory for charged fluids


An improved density functional theory (DFT) for an inhomogeneous charged system (including electrolyte and/or polyelectrolyte) is proposed based on fundamental measure theory, thermodynamic perturbation theory and mean-spherical approximation. Our DFT combines the existing treatment of hard-sphere contributions using fundamental measure theory (FMT) with a new treatment of the electrostatic correlations for the non-bonded ions and chain connectivity that are approximated by employing a first-order Taylor expansion, with the reference fluid density determined using the technique from Gillespie et al. [D. Gillespie et al., J. Phys.: Condens. Matter, 2002, 14, 12129]. We show that the first-order Taylor expansion for the non-bonded electrostatic correlations yields numerically comparable results to the more involved second-order expansion. Furthermore, we find that the existing treatment of the chain connectivity correlation predicts a spurious layer-by-layer phase at moderately large Bjerrum lengths, which is avoided in our new treatment. These simplifications and improvements should significantly facilitate the implementation and reduce the computational cost.

Additional Information

© 2018 The Royal Society of Chemistry. The article was received on 21 Mar 2018, accepted on 12 Jun 2018 and first published on 13 Jun 2018. The Dow Chemical Company is acknowledged for funding and for permission to publish the results. We thank Prof. Lutful Bari Bhuiyan for providing the simulation data in Fig. 1.

Additional details

August 19, 2023
October 18, 2023