Polarization effects in molecular dynamics simulations of glass-formers Ca(NO3)2⋅nH2O, n=4, 6, and 8

Abstract

Monte Carlo simulation strategies for computing the wetting properties of fluids at geometrically rough surfaces J. Chem. Phys. 135, 184702 (2011) Semi-bottom-up coarse graining of water based on microscopic simulations J. Chem. Phys. 135, 184101 (2011) Hydrophobic interactions in presence of osmolytes urea and trimethylamine-N-oxide J. Chem. Phys. 135, 174501 (2011) Potential of mean force between identical charged nanoparticles immersed in a size-asymmetric monovalent electrolyte J. Chem. Phys. 135, 164705 (2011) Additional information on J. Chem. Phys. Thermodynamics, equilibrium structure, and dynamics of glass-forming liquids Ca͑NO 3 ͒ 2 · nH 2 O, n = 4, 6, and 8, have been investigated by molecular dynamics ͑MD͒ simulations. A polarizable model was considered for H 2 O and NO 3 − on the basis of previous fluctuating charge models for pure water and the molten salt 2Ca͑NO 3 ͒ 2 · 3KNO 3 . Similar thermodynamic properties have been obtained with nonpolarizable and polarizable models. The glass transition temperature, T g , estimated from MD simulations was dependent on polarization, in particular the dependence of T g with electrolyte concentration. Significant polarization effects on equilibrium structure were observed in cation-cation, cation-anion, and water-water structures. Polarization increases the diffusion coefficient of H 2 O, but does not change significantly the diffusion coefficients of ions. Viscosity decreases upon inclusion of polarization, but the conductivity calculated with the polarizable model is smaller than the nonpolarizable model because polarization enhances anion-cation interactions.

Molecular Dynamics Simulations of Ionic Liquids and Electrolytes Using Polarizable Force Fields

“…The fluctuating charge model has been applied to aqueous electrolytes, , molten salts, ,− and ionic liquids. , However, most of these simulations are performed with self-written MD codes as only LAMMPS, earlier versions of CHARMM, and nonofficial versions of GROMACS have implemented a fluctuating charge algorithm. This explains the far less common use of these polarizable method compared to Drude oscillators or induced point dipoles.…”

Extension of the CL&Pol Polarizable Force Field to Electrolytes, Protic Ionic Liquids, and Deep Eutectic Solvents

“…12,13 Solutions of alkali metal cations (lithium, sodium) in ionic liquids make up safe, non-flammable electrolytes that offer new perspectives for designing batteries of increased their capacity and charge-discharge timescales. [14][15][16][17] Several techniques can be used to incorporate polarization explicitly in force fields, such as point induced dipoles or Drude induced dipoles, as well as fluctuating charges, but all may suffer from instability issues, [18][19][20][21][22][23][24] especially in systems with strong electrostatic interactions, so building a robust polarizable force field is challenging.…”

“…Several techniques can be used to incorporate polarization explicitly in force fields, such as point-induced dipoles or Drude-induced dipoles, as well as fluctuating charges, but all may suffer from instability issues, − especially in systems with strong electrostatic interactions, so building a robust polarizable force field is challenging.…”

Distributed Polarizability Models for Imidazolium-Based Ionic Liquids

“…Nitrate ions have been simulated by molecular dynamics with polarizable models. ,,− Salvador et al studied an aqueous nitrate ion using an anisotropic polarizability model with an α̅ of 26.3 a.u . Yan et al used the Thole’s model for nitrate in ionic liquids, with α̅ equal to 23, 32.8, or 30.4 a.u .…”