Interatomic potentials of Mg ions in aqueous solutions: structure and dehydration kinetics

Zhang, Xinxing; Álvarez‐Lloret, Pedro; Chass, Greg; Tommaso, Devis Di

doi:10.1127/ejm/2019/0031-2815

Cited by 16 publications

(20 citation statements)

References 70 publications

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“…Di Tommaso and co-workers have conducted a detailed assessment of several nonpolarizable interatomic potentials for hydrated Mg 2 + by computing the energetic (gas phase dissociation reaction of Mg (H 2 O) 6 ), structural (Mg-water radial and angular distribution functions), dynamic (velocity-autocorrelation function of Mg), and kinetic (free energy of Mg-dehydration) properties. [46] Overall, the potential model of Duboue-Dijon (ECC big) provided the best agreement with respect to quantum mechanical and experimental reference data. The retardation factor associated with the water subpopulations of MgCl 2 was determined with the approach used for ab initio MD ( Figure S15 in Supporting Information), from which the hydration numbers of MgCl 2 (aq) was computed as a function of the salt concentration.…”

Section: Concentration-dependent Dielectric Spectroscopy Of Mgcl 2 Somentioning

confidence: 89%

“…Each system was subject to 6 ns of classical MD (NPT) simulations to equilibrate the cell volume using the Mg−O and Mg−Cl Lennard Jones potential parameterized by Aqvist [44] together with the SPC/E water model [45] . This combination of force fields has been shown to provide a reasonable description of the structure and dynamic properties of hydrated Mg 2+ [46] . The last configuration was used to initiate ab initio MD.…”

Section: Methodsmentioning

confidence: 99%

“…[45] This combination of force fields has been shown to provide a reasonable description of the structure and dynamic properties of hydrated Mg 2 + . [46] The last configuration was used to initiate ab initio MD. Table S3 (Supporting Information) reports the percentages of contact ion pairs (CIP), solvent-shared ion pairs (SSHIP), and solvent-separated ion pairs (SSIP) in the 0.1-2.8 mol kg À 1 MgCl 2 solutions.…”

Section: Simulation Protocolmentioning

confidence: 99%

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Hydrogen‐Bond Structure and Low‐Frequency Dynamics of Electrolyte Solutions: Hydration Numbers from ab Initio Water Reorientation Dynamics and Dielectric Relaxation Spectroscopy

et al. 2020

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We present an atomistic simulation scheme for the determination of the hydration number (h) of aqueous electrolyte solutions based on the calculation of the water dipole reorientation dynamics. In this methodology, the time evolution of an aqueous electrolyte solution generated from ab initio molecular dynamics simulations is used to compute the reorientation time of different water subpopulations. The value of h is determined by considering whether the reorientation time of the water subpopulations is retarded with respect to bulk-like behavior. The application of this computational protocol to magnesium chloride (MgCl 2) solutions at different concentrations (0.6-2.8 mol kg À 1) gives h values in excellent agreement with experimental hydration numbers obtained using GHz-to-THz dielectric relaxation spectroscopy. This methodology is attractive because it is based on a well-defined criterion for the definition of hydration number and provides a link with the molecular-level processes responsible for affecting bulk solution behavior. Analysis of the ab initio molecular dynamics trajectories using radial distribution functions, hydrogen bonding statistics, vibrational density of states, water-water hydrogen bonding lifetimes, and water dipole reorientation reveals that MgCl 2 has a considerable influence on the hydrogen bond network compared with bulk water. These effects have been assigned to the specific strong Mg-water interaction rather than the Cl-water interaction.

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Section: Concentration-dependent Dielectric Spectroscopy Of Mgcl 2 Somentioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Simulation Protocolmentioning

confidence: 99%

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Hydrogen‐Bond Structure and Low‐Frequency Dynamics of Electrolyte Solutions: Hydration Numbers from ab Initio Water Reorientation Dynamics and Dielectric Relaxation Spectroscopy

et al. 2020

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“…61 The VACF is very sensitive to the local ion hydration environment and changes in the profiles of this time correlation function, such as oscillatory behaviour and position of the first minimum (t 0 ), can be used as descriptors of the strength of ion interaction with the surrounding water molecules and of the rigidity of the interatomic vibration. 22 The VACFs of Na + (t 0 = 0.1 ps), K + (t 0 = 0.16 ps), and Cs + (t 0 = 0.5 ps) in particular, display a smooth decay, which suggests a weak caging effect by the solvent; this explains the facile kinetics of dehydration of these cations. The lithium ion shows a much sharper first minimum (t 0 = 0.04 ps) followed by a marked oscillatory behavior because of the more rigid interatomic vibration between the smaller Li + with the surrounding hydration cage.…”

Section: Caging Effect In the Hydration Shell Of Ionsmentioning

confidence: 96%

“…These restraints can limit the characterization of the dynamics of solvent exchange in the first hydration shell of metal ions such as Mg 2+ , which mean residence time in the first hydration shell is of the order of microseconds. 21,22 We have therefore complemented the results from AIMD with metadynamics-biased classical MD simulations, which have been used to elucidate the water exchange reaction pathways around metal ions.…”

Section: Introductionmentioning

confidence: 99%

Solution chemistry effects on the solvation shell of metal ions

Wang¹,

Toroz²,

Kim³

et al. 2020

Preprint

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<div> As natural aqueous solutions are far from being pure water, being rich in ions, the properties of solvated ions are of relevance for a wide range of systems, including biological and geochemical environments. We conducted ab initio and classical MD simulations of the alkaline earth metal ions Mg2+ and Ca2+ and of the alkali metal ions Li+, Na+, K+ and Cs+ in pure water and electrolyte solutions containing the counterions Cl– and SO42–. Through a detailed analysis of these simulations, this study reports on the effect of solution chemistry (composition and concentration of the solution) to the ion–water structural properties and interaction strength, and to the dynamics, hydrogen bond network, and low-frequency dynamics of the ionic solvation shell. Except for the ion–water radial distribution function, which is weakly dependent on the counter-ions and concentrations, we found that all other properties can be significantly influenced by the chemical characteristics of the solution. Calculation of the velocity autocorrelation function of magnesium ions, for example, shows that chlorine ions located in the second coordination shell of Mg2+ weaken the Mg(H2O)62+ hydration ‘cage’ of the cation. The result reported in this study suggest that ionic solvation shell can be significantly influenced by the interactions between other ions present in solution ions, especially those of opposite charge. In more general terms, the chemical characteristics of the solution, including the balance between ion-solvent and ion-ion interactions, could result in significant differences in behavior and function of the ionic solvation shell. </div>

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