Resonance Raman and fluorescence spectra of 1.8 dihydroxyanthraquinone in n-alkanes at low temperature. Evidence for excited state proton transfer

Abstract

The resonance Raman and fluorescence spectra of 1.8 dihydroxyanthraquinone in n‐hexane and n‐heptane at 8 K have been measured. By using various exciting lines of an Ar⁺ laser, well resolved site selection spectra were obtained and evidence was found for the existence of at least two emitting excited states. The detailed analysis of the higher energy transition permitted identification of the totally symmetric vibrational modes and evaluation of the displacement of the minima of the potential surfaces of the ground and the dipole allowed excited states. The lower energy transition was interpreted in terms of an excited state relaxation mechanism involving proton transfer.