Fig. 4.

Characteristics of the excitonic states from MD simulation. (A) Correlation functions of vibrational amplitudes, g(R,ω) for three specific frequencies: 1.670 cm⁻¹ (black line), 1,682 cm⁻¹ (red line), and 1,694 cm⁻¹ (blue line). The three curves show that the intermolecular correlation extends to longer distance for exciton states closer to the maximum of the band. (B) Participation ratio, η(ω) (red line), and its standard deviation (bars). The asterisks show the frequencies we used for the calculation of g(R,ω).