Fig. 4. (a) Double square well model: potential; energies and probability density distributions of the ground and first excited states. WOH and WCH3 are width of the two wells; d is the distance between the wells; DOH; DCH3 are the well depths and ΔE is the excitation energy between the ground and the first excited states. (b) Excitation energies (eV) obtained from the double square well model with different inter-cavity distances d and well depths DOH. The other parameters are: DCH3 eV, WOH = 2.2 Å and WCH3 = 2.5 Å. The experimental values indicated in the figure are taken from ref. 21 and 63 and the references therein.
