Thermophysical properties of water using reactive force fields

Gittus, Oliver R.; Bresme, Fernando

doi:10.1063/5.0057868

Cited by 12 publications

(3 citation statements)

References 150 publications

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“…Yeh and Hummer and Dünweg and Kremer , derived an equation based on a hydrodynamic model of a particle immersed in a solvent of viscosity η, with the particle moving on a periodic simulation cell, D 0 ≈ D normalP normalB normalC + ξ k normalB T 6 π η L where D 0 is the diffusion coefficient for an infinite (macroscopic) system, D PBC is the diffusion coefficient obtained in a simulation box of length L and ξ = 2.837297 for a periodic cubic box. This equation has been tested recently in molecular dynamics simulations of reactive force fields of water and to obtain shear viscosities from the finite size effects of D PBC , for a variety of fluid mixtures, including one RTIL ([BMIM] [NTf 2 ]) . The finite size correction alone cannot account for the large underestimation of the diffusion coefficient observed in several RTILs force fields, which is reflected in an underestimation of the simulated ionic conductivities (about 1 order of magnitude) of imidazoium RTILs …”

Section: Simulationsmentioning

confidence: 99%

Theory and Simulations of Ionic Liquids in Nanoconfinement

et al. 2023

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Room-temperature ionic liquids (RTILs) have exciting properties such as nonvolatility, large electrochemical windows, and remarkable variety, drawing much interest in energy storage, gating, electrocatalysis, tunable lubrication, and other applications. Confined RTILs appear in various situations, for instance, in pores of nanostructured electrodes of supercapacitors and batteries, as such electrodes increase the contact area with RTILs and enhance the total capacitance and stored energy, between crossed cylinders in surface force balance experiments, between a tip and a sample in atomic force microscopy, and between sliding surfaces in tribology experiments, where RTILs act as lubricants. The properties and functioning of RTILs in confinement, especially nanoconfinement, result in fascinating structural and dynamic phenomena, including layering, overscreening and crowding, nanoscale capillary freezing, quantized and electrotunable friction, and superionic state. This review offers a comprehensive analysis of the fundamental physical phenomena controlling the properties of such systems and the current state-of-the-art theoretical and simulation approaches developed for their description. We discuss these approaches sequentially by increasing atomistic complexity, paying particular attention to new physical phenomena emerging in nanoscale confinement. This review covers theoretical models, most of which are based on mapping the problems on pertinent statistical mechanics models with exact analytical solutions, allowing systematic analysis and new physical insights to develop more easily. We also describe a classical density functional theory, which offers a reliable and computationally inexpensive tool to account for some microscopic details and correlations that simplified models often fail to consider. Molecular simulations play a vital role in studying confined ionic liquids, enabling deep microscopic insights otherwise unavailable to researchers. We describe the basics of various simulation approaches and discuss their challenges and applicability to specific problems, focusing on RTIL structure in cylindrical and slit confinement and how it relates to friction and capacitive and dynamic properties of confined ions.

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Section: Simulationsmentioning

confidence: 99%

Theory and Simulations of Ionic Liquids in Nanoconfinement

et al. 2023

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“…This decomposition was extensively studied through molecular simulations of hard-spheres and Lennard-Jones binary fluids [7]. Very recent work completed this picture by highlighting the effect of the mass dipole [10] (i.e., the first moment of the mass distribution in the molecules). If we take the example of aqueous mixtures, the socalled chemical component has been related to the hydrophobic/hydrophilic nature of the solutes, in particular, to the strength of their hydrogen-bond interactions with water [3,11,12].…”

Section: Introductionmentioning

confidence: 99%

On the validity of some equilibrium models for thermodiffusion

Araujo-Rocha,

Diaz-Marquez,

Stirnemann

2024

Comptes Rendus. Chimie

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When applied to binary solutions, thermal gradients lead to the generation of concentration gradients and thus to inhomogeneous systems. While being known for more than 150 years, the molecular origins for this phenomenon are still debated, and there is no consensus on the underlying physical models or theories that could explain the amplitude of the concentration gradient in response to a given temperature gradients. Notably, there have been some attempts to relate this nonequilibrium, steady-state manifestation, to equilibrium properties of these solutions, for example, to the temperature dependence of the self-diffusion coefficient or to the solvation free energies of each of their components. Here, we use molecular dynamics simulations on dilute solutions containing molecular-size solutes, both in a thermophoretic setting as well as under equilibrium conditions, to test the validity of such models. We show that these approaches are inadequate and lead to completely uncorrelated estimates as compared to those based on the out-of-equilibrium measurements. Crucially, they fail to explain the strong mass dependence (to which thermodynamics or single-particle diffusion are insensitive) observed in the simulations and measured in the experiments. However, our results suggest an interesting correlation between the amplitude of the short-time molecular motion and that of the concentration gradient that would deserve future investigations.

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“…All the elements needed to consider amino acids were parameterized, including, in particular, nitrogen, sulfur and counter ions. This force field has been updated twice in 2017 5 and 2018 6 with a better description of the weak forces and has become the well-none force field CHON-2017_weak force field used in numerous works [7][8][9] .…”

Section: Introductionmentioning

confidence: 99%

Development of a novel ReaxFF reactive potential for organochloride molecules

Wolf

Bégué

Vallverdu

2022

The Journal of Chemical Physics

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This article presents a new reactive potential in the ReaxFF formalism. It aims to include the chlorine element, and opens up the fields of use of ReaxFF to the whole class of organochloride compounds including conjugated or aromatic groups. Numerous compounds in this family raise global awareness due to their environmental impact, and such a reactive potential will help investigate their degradation pathways. The new force field belongs to the aqueous branch. The force field parameters were fitted against high-level quantum chemistry calculations, including CASSCF/NEVPT2 calculations and density functional theory calculations, and its accuracy was evaluated using a validation set. The root means square deviation against quantum mechanics energies is 0.38 eV (8.91 kcal/mol). From a structural point of view, the root means square deviation is about 0.06Å for the bond lengths, 11.86{degree sign} for the angles and 4.12{degree sign} for the dihedral angles. With CHONCl-2022_weak new force field, we successfully investigated the regioselectivity for nucleophilic or electrophilic attacks on polychlorinated biphenyls (PCB), which are toxic and permanent pollutants. The rotation barriers along the bond linking the two benzene rings, which is crucial in the toxicity of these compounds, are well reproduced by CHONCl-2022_weak. Then our new reactive potential is used to investigate the chlorobenzene atmospheric oxidation, initiated by a hydroxyl radical. The reaction pathways computed with ReaxFF agree with the quantum mechanics results. We showed that, in the presence of dioxygen molecules, the oxidation of chlorobenzene likely leads to the formation of highly oxygenated compounds after the abstraction of hydrogen radicals.

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Thermophysical properties of water using reactive force fields

Cited by 12 publications

References 150 publications

Theory and Simulations of Ionic Liquids in Nanoconfinement

Theory and Simulations of Ionic Liquids in Nanoconfinement

On the validity of some equilibrium models for thermodiffusion

Development of a novel ReaxFF reactive potential for organochloride molecules

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