Excitonic coupling in van der waals complexes: The anisole dimers

We report on the determination of the excitonic coupling occurring between the two anisole molecular units bound to form the anisole dimer in the gas phase. The experimental data are summarized and then analyzed in terms of time-independent perturbation theory. The effective perturbation term for the molecular hamiltonian giving rise to the excitonic coupling is determined. The relative relevance of different coupling terms in the hamiltonian of the system is discussed as well.