Electro-optical properties from CC2 Calculations: A comparison between theoretical and experimental results

The coupled cluster CC2 method has been employed for the computation of dipole moments and static first order hyperpolarizability of a large size push–pull molecule with an extended π electron system. The results are critically compared with the outcomes of electro-optical absorption measurements. CC2 ground and excited state dipole moments are slightly overestimated with respect to the experimental ones, but their differences are well reproduced; good agreement has also been found for absorption wavelengths. Sum of state computations of the static first hyperpolarizability highlight the importance of at least two excited states.