A Critical Look at Methods for Calculating Charge Transfer Couplings Fast and Accurately

Abstract

We present here a short and subjective review of methods for calculating charge transfer couplings. Although we mostly focus on Density Functional Theory, we discuss a small subset of semiempirical methods as well as the adiabatic-to-diabatic transformation methods typically coupled with wavefunction-based electronic structure calculations. In this work, we will present the reader with a critical assessment of the regimes that can be modelled by the various methods -their strengths and weaknesses. In order to give a feeling about the practical aspects of the calculations, we also provide the reader with a practical protocol for running coupling calculations with the recently developed FDE-ET method.

Nonlocal Subsystem Density Functional Theory

“…This is probably because in sDFT, the distribution of electron densities are usually more localized compared to the electron density of the supersystem. [43][44][45] Thus, when developing nonlocal NAKEs, KEDFs must be able to correctly simulate both homogeneous and non-homogeneous systems, and be numerically stable.…”

“…Even though nonlocal KEDFs have a long history in OF-DFT simulations, − to the best of our knowledge they have not yet been employed as NAKEs. This is probably because in sDFT, the distribution of electron densities is usually more localized compared to the electron density of the supersystem. − Thus, when developing nonlocal NAKEs, KEDFs must be able to correctly simulate both homogeneous and nonhomogeneous systems and be numerically stable.…”

Fast Method for Calculating Spatially Resolved Heterogeneous Electron-Transfer Kinetics and Its Application to Graphene with Defects

“…30,31 Some of these approaches are implemented as standard methods in quantum chemical software packages. 30 Most of these methods have been successfully applied to the homogeneous charge transfer from a molecule to a molecule. There are also attempts to implement some approaches for periodic systems, where the quantum mechanical problem is solved in the plane-wave basis.…”

“…The calculation of the electronic coupling is a fairly nontrivial problem. There are quite a few different approaches based both on wave function-based quantum chemical methods, such as generalized Mulliken–Hush (GMH) and fragment charge difference (FCD), and DFT-based approaches, such as frozen-density embedding (FDE) formalism, constrained DFT (CDFT), and fragment orbital DFT (FODFT). , Some of these approaches are implemented as standard methods in quantum chemical software packages . Most of these methods have been successfully applied to the homogeneous charge transfer from a molecule to a molecule.…”

Efficient Constrained Density Functional Theory Implementation for Simulation of Condensed Phase Electron Transfer Reactions

“…A variety of theoretical methods are available for modeling the ET parameters in eq . For | H ab |, these include the generalized Mulliken Hush (GMH) method, , localization and block diagonalization methods, − and constrained density functional theory (CDFT). − A more exhaustive list of methods can be found in the literature ,− and we refer the interested readers to these and references therein for a comparison of the different approaches. In this context, however, we highlight that CDFT is a particularly appealing alternative to compute | H ab | because it combines the computational efficiency of traditional DFT with often great accuracy, ,, except in pathological cases where fractional charge is transferred .…”