(e -t/τ nπ * -e -t/τ ππ * ) (8b) Population dynamics for models with a = 5.5 Å are qualitatively similar to those of the monomer. For the latter, we find a ππ * lifetime of ∼1.2 ps, which is longer than calculated with more sophisticated methods, ∼100-400 fs. We stress that here, for the monomer, we use rAM1/FOMO-CIS including three orbitals only to enable more direct comparison to results for the tetramers. The nπ * lifetime for the monomer is ∼1 ps, which is again slower than reported in other computational works, ∼100-500 fs. The recovery time of the ground state τ S 0 is ∼2.4 ps.