The temperature dependence of the symmetry factor for a model Fe<sup>3+</sup>(aq)/Fe<sup>2+</sup>(aq) redox half reaction

Drechsel-Grau, Christof; Sprik, Michiel

doi:10.1080/00268976.2015.1066897

Cited by 3 publications

(6 citation statements)

References 70 publications

(138 reference statements)

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“…These values are in excellent agreement with the estimates of 1.97 and 2.10 Å derived from extended X-ray absorption fine structure (EXAFS) experiments . Our findings are also consistent with results of previous simulations. − Similarly, the first peak in the g Fe–H ( r ) shifts toward shorter distances by 0.04 Å. Hence, we conclude that the present simulations at constant Fermi energy yield a very good structural description of the reduced and oxidized species.…”

Section: Constant Fermi-level Simulationsupporting

confidence: 92%

Redox Levels through Constant Fermi-Level ab Initio Molecular Dynamics

Bouzid

Pasquarello

2017

J. Chem. Theory Comput.

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We develop a method to determine redox levels of half reactions through the use of ab initio molecular dynamics evolving at constant Fermi energy. This scheme models the effect of an electrode by controlling the charge transfer between the single-particle energy levels of the system and an electron reservoir set at a given potential during the dynamics. Like the thermodynamic integration method, our scheme does not require a priori knowledge of the products of the reaction, which can simply be obtained by driving the reaction through the variation of the Fermi level. The simulations are performed subject to periodic boundary conditions in the absence of any counterelectrode. We extract the redox level from the evolution of the Kohn-Sham energies upon charging (or discharging) the system. Using Janak's theorem and assuming a quadratic evolution of the Kohn-Sham energy of the highest occupied state upon charging, we demonstrate that our scheme for the determination of redox levels is equivalent to the thermodynamic integration method. The approach is illustrated for the redox couples Fe/Fe, HO/HO, and MnO/MnO in aqueous solution and yields redox potentials differing by less than 0.1 eV from respective ones achieved with the thermodynamic integration method.

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Section: Constant Fermi-level Simulationsupporting

confidence: 92%

Redox Levels through Constant Fermi-Level ab Initio Molecular Dynamics

Bouzid

Pasquarello

2017

J. Chem. Theory Comput.

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“…We note that important insights have been arrived at by means of equilibrium simulations which can address aspects of the problem. For example, the variation of interface properties with electron chemical potential can be investigated by adding electrons to the computational cell 2 , and dynamic simulations to determine the symmetry factor associated with the detachment of an ion have been performed 3 .…”

Section: Introductionmentioning

confidence: 99%

Efficient electron open boundaries for simulating electrochemical cells

Horsfield

Todorov

2018

Phys. Rev. B

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Non-equilibrium electrochemistry raises new challenges for atomistic simulation: we need to perform molecular dynamics for the nuclear degrees of freedom with an explicit description of the electrons, which in turn must be free to enter and leave the computational cell. Here we present a limiting form for electron open boundaries that applies when the magnitude of the electric current is determined by the drift and diffusion of ions in solution, and which is sufficiently computationally efficient to be used with molecular dynamics. We demonstrate its capabilities by way of tight binding simulations of a parallel plate capacitor with and without a dimer situated in the space between the plates

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“…This result suggests that the aqueous Fe 2+/3+ redox system behaves linearly with respect to the solvent response, as reported in earlier studies. [2,[5][6][7] Table 1.. Comparison of structural properties of the first and second solvation shell (SS) of water around Fe 2+ and Fe 3+ ions in our simulations with other data from simulations (Sim.)…”

Section: ∆Ementioning

confidence: 96%

“…This result suggests that the aqueous Fe 2þ=3þ redox system behaves linearly with respect to the solvent response, as reported in earlier studies. [2,[5][6][7] Interestingly, the curvature and the location of the minima in the free energy profiles differ for the two functionals. 1.07 (1.02) [a] l Fe 3þ 0.87 (0.70) [a] 1.07 (0.77) [a] λ 0.88 � 0.02 1.10 � 0.01 ΔF 0.50 � 0.02 0.26 � 0.01…”

Section: Gaussian Functions Are Used To Fit These Probability Distrib...mentioning

confidence: 99%

“…Electron transfer (ET) reactions are very important in many chemical and biological processes and are subjected to numerous experimental and theoretical investigations. [1] In this regard, aqueous ferrous-ferric ET has attracted many theoretical [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] studies as a prototype of more complex ET processes. In water solvent, both ferrous and ferric ions remain in stable hexaaqua complex form and build a well defined solvent structure around them.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hybrid Functional and Plane Waves based Ab Initio Molecular Dynamics Study of the Aqueous Fe²⁺/Fe³⁺ Redox Reaction**

et al. 2022

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Kohn-Sham density functional theory and plane wave basis set based ab initio molecular dynamics (AIMD) simulation is a powerful tool for studying complex reactions in solutions, such as electron transfer (ET) reactions involving Fe 2+ /Fe 3+ ions in water. In most cases, such simulations are performed using density functionals at the level of Generalized Gradient Approximation (GGA). The challenge in modelling ET reactions is the poor quality of GGA functionals in predicting properties of such open-shell systems due to the inevitable self-interaction error (SIE). While hybrid functionals can minimize SIE, AIMD at that level of theory is typically 150 times slower than GGA for systems containing ∼100 atoms. Among several approaches reported to speed-up AIMD simulations with hybrid functionals, the noise-stabilized MD (NSMD) procedure, together with the use of localized orbitals to compute the required exchange integrals, is an attractive option. In this work, we demonstrate the application of the NSMD approach for studying the Fe 2+ /Fe 3+ redox reaction in water. It is shown here that long AIMD trajectories at the level of hybrid density functionals can be obtained using this approach. Redox properties of the aqueous Fe 2+ /Fe 3+ system computed from these simulations are compared with the available experimental data for validation.

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The temperature dependence of the symmetry factor for a model Fe³⁺(aq)/Fe²⁺(aq) redox half reaction

Cited by 3 publications

References 70 publications

Redox Levels through Constant Fermi-Level ab Initio Molecular Dynamics

Redox Levels through Constant Fermi-Level ab Initio Molecular Dynamics

Efficient electron open boundaries for simulating electrochemical cells

Hybrid Functional and Plane Waves based Ab Initio Molecular Dynamics Study of the Aqueous Fe²⁺/Fe³⁺ Redox Reaction**

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The temperature dependence of the symmetry factor for a model Fe3+(aq)/Fe2+(aq) redox half reaction

Cited by 3 publications

References 70 publications

Redox Levels through Constant Fermi-Level ab Initio Molecular Dynamics

Redox Levels through Constant Fermi-Level ab Initio Molecular Dynamics

Efficient electron open boundaries for simulating electrochemical cells

Hybrid Functional and Plane Waves based Ab Initio Molecular Dynamics Study of the Aqueous Fe2+/Fe3+ Redox Reaction**

Contact Info

Product

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The temperature dependence of the symmetry factor for a model Fe³⁺(aq)/Fe²⁺(aq) redox half reaction

Hybrid Functional and Plane Waves based Ab Initio Molecular Dynamics Study of the Aqueous Fe²⁺/Fe³⁺ Redox Reaction**