Spectroscopic signatures of triplet states in acenes

Triplet states are of great interest in current lightenergy conversion strategies, as their creation through the singlet fission processes can overcome the ShockleyQueisser limit. We analyze the experimental possibilities for the detection of triplet states with ground state and linear response time dependent density functional calculations. We show that triplets can be clearly detected through their optical properties, that can be seen in photoabsorption and photeoelectron spectra, as well as in vibrational properties, that can be studied via infrared spectra.