Free Energies of Redox Half-Reactions from First-Principles Calculations

Abstract

Quantitative prediction of the energetics of redox half-reactions is still a challenge for modern computational chemistry. Here, we propose a simple scheme for reliable calculations of vertical ionization and attachment energies, as well as of redox potentials of solvated molecules. The approach exploits linear response approximation in the context of explicit solvent simulations with spherical boundary conditions. It is shown that both vertical ionization energies and vertical electron affinities, and, consequently redox potentials, exhibit linear dependence on the inverse radius of the solvation sphere. The explanation of the linear dependence is provided, and an extrapolation scheme is suggested. The proposed approach accounts for the specific short-range interactions within hybrid DFT and effective fragment potential approach as well as for the asymptotic system-size effects. The computed vertical ionization energies and redox potentials are in excellent agreement with the experimental values.

An interaction energy driven biased sampling technique: A faster route to ionization spectra in condensed phase

“…There has been significant progress in modeling the redox reactions accurately using Marcus theory and linear response approximations. [31][32][33][34][35][36] Both electron attachment and detachment processes result in a change in the net charge of the chromophore and cause a significant redistribution of electron density. Therefore, IE and EA of a chromophore is expected to be significantly affected by the environment.…”

Efficient modeling of liquid phase photoemission spectra and reorganization energies: Difficult case of multiply charged anions

“…The configurations should be sampled by molecular dynamics (MD). Note that the cluster‐continuum separation can be as well used for calculating the IE, redox potentials, and reorganization energies by means of the extrapolation of the gas phase results …”

“…Note that the clustercontinuum separation can be as well used for calculating the IE, redox potentials, and reorganization energies by means of the extrapolation of the gas phase results. [35] Most of the theoretical studies focus on the estimation of the peak position, that is, on the calculations of the IE, reporting on how loosely the electron is bound to the solute molecule and how this changes on solvation. Nonetheless, the photoemission measurements carry more information.…”

Distinct Electron Conductance Regimes in Bacterial Decaheme Cytochromes

“…[19] We calculated redox properties using the linear response approximation (LRA) within aQ M/MM scheme. [23] Using quantum-mechanical potentials instead of classic force fields improves the predictive power of the calculations and allows one to compute absolute values of the redox potentials that can be directly compared to the experimental measurements. [24,25] Theu ncertainties in these calculations are due to Gibbs free energy of the reference electrode and approximation of Born correction.…”