Density Functional Physicality in Electronic Coupling Estimation: Benchmarks and Error Analysis.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Constrained density functional theory configuration interaction (CDFT-CI) is used for electronic coupling estimates.
• The accuracy of CDFT-CI is sensitive to the choice of density functional.

Purpose of the Study:

• To identify key density functional properties that determine the accuracy of CDFT-CI electronic coupling estimates.
• To develop a metric for predicting errors in electronic coupling calculations.

Main Methods:

• Analysis of orbital multielectron self-interaction error (OMSIE), vertical electron affinity (VEA), and vertical ionization potential (VIP).
• Derivation of an error metric (η) connecting these properties to electronic coupling and overlap integrals.
• Evaluation of density functionals BH&HLYP and LRC-ωPBEh for electron and hole transfer.

Main Results:

• OMSIE, VEA, and VIP are identified as crucial indicators inherited from density functionals.
• The derived error metric η effectively predicts errors in CDFT-CI electronic coupling.
• BH&HLYP and LRC-ωPBEh are recommended as optimal functionals for electron and hole transfer, respectively.

Conclusions:

• The physical correctness of a density functional directly impacts the accuracy of CDFT-CI electronic coupling calculations.
• The error metric η serves as a valuable tool for selecting appropriate density functionals for electronic coupling studies.
• This work provides a pathway to improve the reliability of computational predictions in electron and hole transfer processes.