MENGER, M.F.S.J. ... et al, 2018. Surface hopping within an exciton picture. An electrostatic embedding scheme. Journal of Chemical Theory and Computation, doi:10.1021/acs.jctc.8b00763.
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.
This paper is closed access until 9 October 2019.
M.F.S.J.M. gratefully acknowledges financial support from the EU Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 642294.