Prediction of electronic couplings for molecular charge transfer using optimally-tuned range-separated hybrid functionals

TL;DR

This study evaluates the accuracy of TDDFT with optimally-tuned range-separated hybrid functionals in predicting electronic coupling matrix elements for charge transfer, showing significant improvements over previous methods.

Contribution

The paper demonstrates that using optimally-tuned range-separated hybrid functionals in TDDFT enhances the accuracy of electronic coupling predictions for charge transfer processes.

Findings

Outperforms previous TDDFT methods in accuracy

Achieves an average deviation of ~12%

Provides insights into sources of remaining errors

Abstract

Electronic coupling matrix elements are important to the theoretical description of electron transfer processes. However, they are notoriously difficult to obtain accurately from time- dependent density functional theory (TDDFT). Here, we use the HAB11 benchmark dataset of coupling matrix elements to assess whether TDDFT using optimally-tuned range-separated hybrid functionals, already known to be successful for the description of charge transfer excitation energies, also allows for an improved accuracy in the prediction of coupling matrix elements. We find that this approach outperforms all previous TDDFT calculations, based on semi-local, hybrid, or non-tuned range-separated hybrid functionals, with a remaining average deviation as low as ~12%. We discuss potential sources for the remaining error.