Electronic and vibrational contributions to the reorganization energy of photosynthetic pigments

Charge transport is dependent on properties such as reorganization energy (λ) and free energy. These quantities are typically estimated applying density functional theory (DFT) to optimized geometries. However, most pigments in photosynthesis conjugated, making delocalization vibrational effects relevant. Here, we calculated energies of 15 molecules relevant using a reliable DFT-based approach. Tuning the functional’s long-range parameter prevents over-delocalization orbitals, while molecular vibrations accounted for via an ensemble method. Results show that tuning decreases λ, but produce distributions affecting charge transfer rates up one order magnitude.