Solitonic energy transfer in a coupled exciton-vibron system

We consider the exciton transfer along a one-dimensional molecular chain. T he exciton motion is influenced by longitudinal vibrations evolving in a To da lattice potential. It is shown hew the soliton solutions of the vibron s ystem coupled to the exciton system induce solitonic exciton transfer. To t his aim the existence of a regime of suppressed energy exchange between the coupled excitonic and vibrational degrees of freedom is established in the case of which a nonlinear Schrodinger equation for the exciton variable is derived. The nonlinear Schrodinger equation possesses soliton solutions co rresponding to coherent transfer of the localized exciton.