Exciton and excitonic polaron in C60

Exciton and excitonic polaron states in C60 molecule are studied theoretically by the tight-binding model and the extended Hubbard interaction. We find that the exciting energies of the lowest singlet and triplet excitons depend sensitively upon the electron correlation. And the excitonic polaron is formed due to the electron-lattice coupling. Relevant experiments in photo-luminescence spectrum of C60 can be explained qualitatively by the present model with moderate interaction strength U ∼ 5.0eV, and V ∼ 2.0eV in our approximation.