Excimer formation may be facilitated by these aggregates, and is therefore absent at more dilute concentrations. Aggregate formation would explain why the decay of the S 1 state at 8 mM is overestimated by the Dover model. If SF or excimer formation were due to aggregates rather than, or in addition to, collisions between molecules, then the pseudo-first-order SF rate constants at 300 mM would not scale linearly with concentration, and the bimolecular rate constant would no longer be applicable. Using the rate constants fit to a system with aggregates would overestimate the rates at more dilute, diffusion-limited concentrations. The underestimation of triplet excitons at 8 mM by the Dover model is partially explained by the underestimation of SF and overestimation of excimer formation: if excimers predominantly result from aggregates and are absent at lower concentrations, then collisions at 8 mM are more likely to result in SF, and more triplet formation.