Laser Excited Emission Spectroscopy of Azulene in the Gas Phase

In this paper we present the results of an experimental study of the radiative decay of the two lowest singlet states Si and S-z of the azulene molecule in the gas phase excited by a Q switched ruby laser ( 14 400 cm-1) and by its second harmonic (28 800 cm~J). Spectroscopic information has been obtained concerning the energy resolved spectra of the SiSo and of the S2Si emission. The quantum yield data for the SiSo decay led to an estimate of the nonradiative decay time of 5i. The branching ratio between the SiSo and the SrSi emissions was utilized for the evaluation of the 52Si radiative decay time. The study of the consecutive two photon SoSiSa excitation leads to an estimate of the S1S2absorption cross section near the electronic origins of the two excited states. The decay characteristics of the lowest excited singlet state of the "isolated" azulene molecule confirm the theoretical prediction concerning nonradiative electronic relaxation in the statistical limit.

Laser Excited Emission Spectroscopy of Azulene in the Gas Phase Academic Article