Photoinduced charge transfer (CT) and excitation energy transfer (EET) are fundamental processes generally occurring in photosynthetic systems, organic photovoltaic and luminescent materials, artificial light-harvesting architectures, DNA π-stacks, and so on. The electronic couplings, which usually refer to the couplings among CT and locally excited (LE) states (the so-called quasi-diabatic states) in CT and EET processes, are of great significance for the dynamics. In this report, I will introduce a new diabatization scheme, named as the fragment particle-hole densities, toward the calculation of these electronic couplings for both singlet and triplet states. In this scheme, the LE and CT states are constructed from the adiabatic excited states by maximally localizing the particle (i.e., electron) and hole densities in terms of predefined molecular fragments. The construction process, after which the electronic couplings are directly obtained, is highly efficient and can be combined with various kinds of preliminary electronic structure calculations as long as the adiabatic excitation energies and transition densities are available. The method also applies to the systems with multiple charge or excitation centers. The application to the absorption spectra of the zinc phthalocyanine aggregates will be discussed. In the last part of this report, I will also discuss the extension of this approach to the singlet fission process where double excitation is important.

Electronic couplings for photoinduced charge transfer and excitation energy transfer based on fragment particle–hole densities

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.