A simple monomer-based model-Hamiltonian approach to combine excitonic coupling and Jahn-Teller theory

The interplay of excitonic and vibronic coupling in coupled chromophores determines the efficiency of exciton localization vs delocalization, or in other words, coherent excitation energy transfer vs exciton hopping. For the investigation of exciton localization in large coupled dimers, a model Hamiltonian approach is derived, the ingredients of which can all be obtained from monomer ab initio calculations alone avoiding costly ab initio computation of the full dimer. The accuracy and applicability of this model are exemplified for the benzene dimer by rigorous comparison to ab initio results.