The ππ * absorption band of the monomer and the tetramer calculated with TD-ωB97X-D/def2-SV(P) for single, model geometries. The monomer geometry was optimized at the B3LYP/def2-SV(P) level; the tetramer geometry (see Fig. ) was constructed from the optimized monomer geometry. (b) The ππ * absorption band of the monomer and the tetramer at T ≈ 300 K. The spectra are obtained using TD-ωB97X-D/def2-SV(P) calculations for 100 snapshots.