FLUORESCENCE PROPERTIES OF FLUORANTHENE AS A FUNCTION OF TEMPERATURE AND ENVIRONMENT

The fluoranthene fluorescence properties were investigated in a variety of environments, i.e. in different solvents and temperatures, in the solid state, and in the vapor phase. The emission maximum was found to be independent of environment. The absorption spectrum in different solvents exhibits only minor changes. In solution, the fluorescence lifetime shows a slight inverse relationship to the solvent dielectric constant. With water/methanol mixtures of varying composition as the solvent, the lifetime decreases linearly with increasing mole fraction of water. At 77 K, the fluoranthene fluorescence lifetime in frozen polar and nonpolar solvents are the same within experimental error. In hexane the fluorescence lifetime is independent of temperature (77 +/- 3 and 82 +/- 7 ns, at room temperature and 77 K, respectively). In methanol the lifetime is 64 +/- 3 ns at room temperature and increases linearly to 80 +/- 4 ns at 77 K. In the vapor phase the lifetime is 32 +/- 1 ns. No fluorescence quantum yield change was observed for either S1 or S2 manifold excitation.