2134/36363 Maximilian F.S.J. Menger Maximilian F.S.J. Menger Felix Plasser Felix Plasser Benedetta Mennucci Benedetta Mennucci Leticia Gonzalez Leticia Gonzalez Surface hopping within an exciton picture. An electrostatic embedding scheme Loughborough University 2018 untagged Chemical Sciences not elsewhere classified Computer Software 2018-12-07 15:13:45 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Surface_hopping_within_an_exciton_picture_An_electrostatic_embedding_scheme/9395564 We report the development and the implementation of an exciton approach that allows ab initio nonadiabatic dynamics simulations of electronic excitation energy transfer in multichromophoric systems. For the dynamics, a trajectory-based strategy is used within the surface hopping formulation. The approach features a consistent hybrid formulation that allows the construction of potential energy surfaces and gradients by combining quantum mechanics and molecular mechanics within an electrostatic embedding scheme. As an application, the study of a molecular dyad consisting of a covalently bound BODIPY moiety and a tetrathiophene group is presented using time-dependent density functional theory (TDDFT). The results obtained with the exciton model are compared to previously performed full TDDFT dynamics of the same system. Our results show excellent agreement with the full TDDFT results, indicating that the couplings that lead to excitation energy transfer (EET) are dominated by Coulomb interaction terms and that charge-transfer states are not necessary to properly describe the nonadiabatic dynamics of the system. The exciton model also reveals ultrafast coherent oscillations of the excitation between the two units in the dyad, which occur during the first 50 fs.