Fluorescence lifetimes of terrylene in solid matrices

We report the fluorescence lifetimes of terrylene in crystalline and amorph ous matrices at room temperature and at 4.2 K. The measurements at 4.2 K sh ould indicate the single molecule natural linewidth limit. We find that the natural linewidth calculated from the bulk lifetime results for terrylene in p-terphenyl, for terrylene in hexadecane, and for terrylene in polyethyl ene systems agrees with low temperature single molecule linewidths. Most im portant, we find that the excited state lifetime is larger than some previo usly determined values, which means that the natural linewidth is narrower for most systems than previously thought. (C) 1999 Elsevier Science B.V. Al l rights reserved.