  The ultrafast relaxation dynamics of tetracene following UV excitation to a
bright singlet state S6 has been studied with time-resolved photoelectron
spectroscopy. With the help of high-level ab-initio multireference perturbation
theory calculations, we assign photoelectron signals to intermediate dark
electronic states S3, S4 and S5 as well as a to a low-lying electronic state
S2. The energetic structure of these dark states has not been determined
experimentally previously. The time-dependent photoelectron yields assigned to
the states S6, S5 and S4 have been analyzed and reveal the depopulation of S6
within 50 fs, while S5 and S4 are populated with delays of about 50 and 80 fs.
The dynamics of the lower-lying states S3 and S2 seem to agree with a delayed
population coinciding with the depopulation of the higher-lying states S4-S6,
but could not be elucidated in full detail due to the low signal levels of the
corresponding two-photon ionization probe processes.
