Localized diabatization applied to excitons in molecular crystals

Area of Science:

• Solid-state physics
• Quantum chemistry
• Computational materials science

Background:

• Traditional ab initio calculations produce delocalized electronic states (adiabatic states) in periodic systems.
• Excitons, often described as bands of extended states, require localization for studying nuclear motion effects on transport.
• Localized descriptions of excitons are beneficial even in band regimes for detailed analysis.

Purpose of the Study:

• To develop and present novel methods for diabatization to extract localized excitons from delocalized bands.
• To provide tools for more accurate ab initio studies of exciton dynamics and energy transfer in solids.
• To enable the investigation of exciton-electron-phonon interactions through localized descriptions.

Main Methods:

• A simple projection method for localized diabatization.
• A generalized Pipek-Mezey localization scheme.
• A variant of the Boys diabatization method.

Main Results:

• Three distinct diabatization methods are proposed for localizing electronic states.
• Two methods rely on localized single-particle Wannier orbitals, while one is independent of them.
• The proposed methods facilitate the study of localized excitons in periodic systems.

Conclusions:

• The developed localized diabatization techniques are valuable for ab initio studies of energy transfer in solids.
• These methods bridge the gap between delocalized band theory and localized excitation descriptions.
• Future research can leverage these techniques to explore exciton transport mechanisms with greater fidelity.