Knowledge Bank

Ab initio CI calculations in an FSGO basis have been carried out the lower excited singlet and triplet states of the title molecules. The calculated $So\to Sn$ and $So\to Tn$ energies were found to be linearly related to the experimentally observed transition energies. Transition energies, polarizations, and oscillator strengths have been compared with experimental data, where available. It was found that this method treats singlet $\pi -\pi \ast$, triplet $\pi -\pi \ast$, singlet $\pi -\pi \ast$, and triplet $\pi -\pi \ast$ transition energies equally well.