Accurate and efficient DFT-based diabatization for hole and electron transfer using absolutely localized molecular...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Chemical Physics

Background:

• Diabatic states and their couplings are crucial for understanding chemical and biochemical processes.
• Accurate computation of these couplings is essential for predicting reaction rates and mechanisms.

Purpose of the Study:

• To develop and validate a novel approach for computing diabatic couplings using density functional theory (DFT) and absolutely localized molecular orbitals (ALMOs).
• To improve the accuracy of diabatic coupling calculations, particularly for electron and hole transfer processes.

Main Methods:

• Utilizing absolutely localized molecular orbitals (ALMOs) to generate variationally optimized diabatic states.
• Employing the symmetrized transition density matrix to evaluate the exchange-correlation contribution for enhanced electronic coupling accuracy.
• Applying the method to diverse systems including conjugated organic molecules (thiophene, pentacene) and DNA base pairs.

Main Results:

• The proposed method accurately computes electronic couplings between ALMO-based diabats.
• Results show high accuracy compared to existing DFT-based diabatization methods for various electron and hole transfer systems.
• The approach remains accurate even with lower tiers of the DFT hierarchy.

Conclusions:

• The ALMO-based approach with a symmetrized transition density matrix provides accurate diabatic couplings.
• This method offers a reliable and accurate ab initio treatment for nonadiabatic processes in condensed phases.
• The findings open possibilities for integrating this method with quantum dynamics simulations.