Vibrational energy relaxation rates in the S2 state of azulene in nitrogen and carbon dioxide

The solvent density dependence of the vibrational energy relaxation rates in the S2 state of azulene has been measured in nitrogen and carbon dioxide at 323.2 and 341 K. The vibrational energy relaxation rate is determined by measuring the time-dependent fluorescence spectra after photo-excitation at 283 nm. The density dependence of the vibrational energy relaxation rate is almost similar to that of the ground state. However, the vibrational energy relaxation rate in the S2 state is faster than that of the ground state if they are compared at the same solvent density.