eV for models with a = 5.5 Å, ∼0.04 eV for tetramer 3.5 Å, and ∼0.08 eV for SAM 3.5 Å. Interestingly, larger absorbance is observed for models with a = 5.5 Å in comparison to those with a = 3.5 Å. This effect is opposite to what is seen for the strong ππ * band in the UV region (Fig. , right). We note that in the simple exciton model (considering an H-aggregate composed of identical monomer geometries with the same non-zero transition dipole moment), a larger enhancement should occur for a smaller separation distance owing to a larger exciton splitting. As discussed previously for the dimeric models, 57 the trend in absorbance observed for the nπ * band upon aggregation is determined by the extent of deviation of the monomers forming an aggregate from the equilibrium, planar C 2h geometry.