Surface Tensions of Molten Binary CaCl2-NaCl, LaCl3-NaCl, and LaCl3-CaCl2 and Ternary LaCl3-CaCI2-NaCl Systems

Igarashi, Kazuo; Iwadate, Yasuhiko; Mochinaga, Junichi

doi:10.1515/zna-1987-0815

Cited by 6 publications

(1 citation statement)

References 9 publications

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“…The hydroxide ions have a higher polarity compared to OH groups in water, represented by larger negative oxygen atomic charges (between −1.32e and −1.02e compared to −0.82e in water), plus some variation in the O–H bond length and H atomic charge (+0.3e to +0.5e compared to +0.41e in water). Therefore, cleavage energies are in a range of 0.15 to 0.25 J/m 2 , which is higher than the surface tension of water (0.072 J/m 2 ), and in a similar range as alkali and earth alkali halides (0.15 to 0.25 J/m 2 ). ,− Several earlier simulation data support values in this range (Table and Table S2 in the Supporting Information). The IFF models of oxides and hydroxides were calibrated to best reproduce these likely surface energies, consistent with the known atomic charges and LJ parameters relative to validated compounds with similar chemistry.…”

Section: Resultsmentioning

confidence: 99%

Accurate Force Fields for Atomistic Simulations of Oxides, Hydroxides, and Organic Hybrid Materials up to the Micrometer Scale

Kanhaiya,

Nathanson,

in ’t Veld

et al. 2023

J. Chem. Theory Comput.

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The simulation of metals, oxides, and hydroxides can accelerate the design of therapeutics, alloys, catalysts, cement-based materials, ceramics, bioinspired composites, and glasses. Here we introduce the INTERFACE force field (IFF) and surface models for α-Al2O3, α-Cr2O3, α-Fe2O3, NiO, CaO, MgO, β-Ca(OH)2, β-Mg(OH)2, and β-Ni(OH)2. The force field parameters are nonbonded, including atomic charges for Coulomb interactions, Lennard-Jones (LJ) potentials for van der Waals interactions with 12–6 and 9–6 options, and harmonic bond stretching for hydroxide ions. The models outperform DFT calculations and earlier atomistic models (Pedone, ReaxFF, UFF, CLAYFF) up to 2 orders of magnitude in reliability, compatibility, and interpretability due to a quantitative representation of chemical bonding consistent with other compounds across the periodic table and curated experimental data for validation. The IFF models exhibit average deviations of 0.2% in lattice parameters, <10% in surface energies (to the extent known), and 6% in bulk moduli relative to experiments. The parameters and models can be used with existing parameters for solvents, inorganic compounds, organic compounds, biomolecules, and polymers in IFF, CHARMM, CVFF, AMBER, OPLS-AA, PCFF, and COMPASS, to simulate bulk oxides, hydroxides, electrolyte interfaces, and multiphase, biological, and organic hybrid materials at length scales from atoms to micrometers. The nonbonded character of the models also enables the analysis of mixed oxides, glasses, and certain chemical reactions, and well-performing nonbonded models for silica phases, SiO2, are introduced. Automated model building is available in the CHARMM-GUI Nanomaterial Modeler. We illustrate applications of the models to predict the structure of mixed oxides, and energy barriers of ion migration, as well as binding energies of water and organic molecules in outstanding agreement with experimental data and calculations at the CCSD(T) level. Examples of model building for hydrated, pH-sensitive oxide surfaces to simulate solid-electrolyte interfaces are discussed.

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