Accurate Free Energies of Aqueous Electrolyte Solutions from Molecular Simulations with Non-polarizable Force Fields

Parsa Habibi, H Mert Polat, Samuel Blazquez, Carlos Vega, Poulumi Dey, Thijs J H Vlugt, Othonas A Moultos

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Non-polarizable force fields fail to accurately predict free energies of aqueous electrolytes without compromising the predictive ability for densities and transport properties. A new approach is presented in which (1) TIP4P/2005 water and scaled charge force fields are used to describe the interactions in the liquid phase and (2) an additional Effective Charge Surface (ECS) is used to compute free energies at zero additional computational expense. The ECS is obtained using a single temperature-independent charge scaling parameter per species. Thereby, the chemical potential of water and the free energies of hydration of various aqueous salts (e.g., NaCl and LiCl) are accurately described (deviations less than 5% from experiments), in sharp contrast to calculations where the ECS is omitted (deviations larger than 20%). This approach enables accurate predictions of free energies of aqueous electrolyte solutions using non-polarizable force fields, without compromising liquid-phase properties.

Original languageEnglish
Pages (from-to)4477-4485
Number of pages9
JournalJournal of Physical Chemistry Letters
Volume15
Issue number16
Early online date18 Apr 2024
DOIs
Publication statusPublished - 25 Apr 2024
Externally publishedYes

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