Single site electronic spectra of free base tetraazaporphin in an n-octane crystal at 5 K

Abstract

Single site fluorescence and absorption spectroscopy of free base tetraazaporphin in an n-octane crystal at 5 K are reported. The vibrational frequencies of the ground state and the first two ππ ∗ singlet excited states were determined from the spectra. There appears to be strong resonant vibronic interference between the second excited state and the underlying manifold of vibrations belonging to the first excited state. There is no indication of the presence of low energy ππ ∗ states.