Charge transfer processes and environmental degrees of freedom: cooperativity and non-linearity

To investigate supramolecular effects in samples with high concentration of push-pull chromophores, we propose a model for interacting polar and polarizable molecules. Each molecule is described in terms of the same two-state picture successfully adopted to model solvated chromophores and electrostatic interactions among different chromophores are introduced. Important supramolecular effects are observed even at the lowest mean-field level, showing up the possibility of tuning molecular polarity from the neutral to the zwitterionic regime or vice versa. Supramolecular effects in excitation spectra are more complex. Here we demonstrate large supramolecular effects beyond mean-field in static optical responses.