Improving the description of solvent pairwise interactions using local solute/solvent three‐body functions. The case of halides and carboxylates in aqueous environment

Abstract

We propose a general strategy to remediate force-field artifacts in describing pairwise interactions among similar molecules M in the vicinity of another chemical species, C, like water molecules interacting at short distance from a monoatomic ion. This strategy is based on introducing a three-body potential energy term that alters the pairwise interactions among M-type molecules when they lie at short range from the species C. In other words the species C is the center of a space domain where the pairwise interactions among the molecules M is altered. Here, we apply it to improve the description of the water interactions provided by the polarizable water model TCPE/2013 in the vicinity of halides, from F − to At − , and of the prototypical carboxylate anion CH 3 COO − . We show the accuracy and the transferability of such an approach to investigate not only the hydration process of single anions but also of a salt solution NH + 4 =Clin aqueous phase. This strategy can be used to remediate the drawbacks of any kind of force fields.

NaCl salts in finite aqueous environments at the fine particle marine aerosol scale

“…That arises from the force field underestimate of the strong water/water repulsion in the compact conformations of large hydrated anion clusters. 31 Regarding alkaline and ammonium cations, we showed our force field to underestimate the cation/water cluster BEs up to 5% compared to quantum data for clusters presenting a partial or complete second hydration shell. 32 That force-field drawback arises a priori from a weak error in describing the energetic of a particular water dimer conformation as compared to quantum data.…”

“…To remediate the two above artifacts without fully redeveloping our force fields and parameter sets, we built up specific short range many-body functions (denoted as U sc ), whose analytical form is close to the U coop one and that improves the modeling of water/water interactions only at the close vicinity of anionic and cationic centers. 31,32 For the present purpose, we used the U sc functions (and their parameters) allowing one to model the hydration of Na + and Clfrom our earlier studies. 31,32 As expected from the above discussion, U sc (Cl -) and U sc (Na + ) destabilizes and stabilizes the ion/water interactions in large hydrated ionic cluster, respectively.…”

“…Whereas most of the available MD simulations of salty aqueous interfaces regard bulk systems (as all the studies mentioned above), we present here MD simulations of ideal fine particle marine aerosols (a brine comprising only [Na + , Cl -] salt) performed by means of the latest version of our ab initio-based polarizable force field. [29][30][31][32] Such ideal aerosols are pivotal reference systems to understand and to analyze data regarding the incorporation of chemical species (like multivalent cations and organic molecules). To this end we simulate droplets comprising about 10 000 (10k), 100 000 (100k) and 1 000 000 (1M) water molecules for [Na + , Cl -] concentrations c corresponding to highly saline water and sea water, i.e.…”

Ion hydration free energies and water surface potential in water nano drops: The cluster pair approximation and the proton hydration Gibbs free energy in solution

“…All the above force-field adjustable parameters allowing to model ion/water interactions are assigned to reproduce geometrical and energetic properties of small clusters as computed from high end quantum computations extrapolated to the complete basis set limit (see Refs 18,19,22 as well as Supplementary Material, Section 1). Note in particular our force fields for halides yield no overpolarization effect on the anion center as compared to the quantum CPMD approach.…”

Hierarchical phenomena in multicomponent liquids: simulation methods, analysis, chemistry

“…24 These potentials have also been applied to model heavy elements in aqueous environments. [25][26][27][28] A similar energy decomposition approach for fitting classical potentials to QM data is the NEMO approach with Gagliardi and coworkers have also extended to develop actinide-water potentials. 29,30 Simulation times of 10 ns or so are achievable with these polarizable force fields for relatively small periodic systems, allowing for highly accurate and wellsampled structural and dynamical data for aqueous solutions.…”