Aggregation effects on two-photon absorption spectra of octupolar molecules

Aggregation effects on two-photon absorption cross sections of an octupolar molecule, 1,3,5-triamino-2,4,6-trinitrobenzene, have been examined by means of density functional theory calculations in combination with molecular dynamic simulations. It is shown that this octupolar molecule becomes polar in solution and forms aggregates due to the presence of hydrogen bonding between molecules, which can induce a strong redshift of the charge-transfer state and significantly alter the TPA cross section.