Single site electronic spectroscopy of free base chlorin in an n-octane crystal at 5 K

Abstract

Single site fluorescence and absorption spectra of free base chlorin in an n-octane crystal at 5 K are reported. The vibrational frequencies of the ground and excited states, Q y, Q x and B, have been determined from the spectra. Evidence is found for a possible nπ ∗ state just below the Q x transition and for resonant vibronic interference between the Q x state and an underlying state's vibronic manifold. The Soret region has no structure and also shows signs of a lower energy nπ ∗ state.