Fluorescence spectrum, anthracene pyrene

Figure 5. MI fluorescence spectrum of LC Fraction V from Synthoil at two excitation wavelengths. BaA = benz[a]anthracene C = chrysene U = unknown P = pyrene (artifact not present in fraction).

FtGURE 15-6 Total luminescence spectra. In (a), ihe total fluorescence spectrum of a mixture of anthracene and ovalene is shown as a three-dimensional plot. In (b). the total fluorescence spectrum ol 8-hydroxybenzo(a]pyrene is shown as a contour plot. Each line represents a particular fluorescence intensity. (Part a from Y. Taimi et ai.. Anal. Chem.. 1978.50. 936A. Figure 11. p. 948A. Part b adapted from J. H. Rho and J. L. Stewart. Anal. Chem., 1978. 50. 620. Figure 2, p. 622. Copyright 1978 Amencan Chemical Society.)... 

Emission spectra at these points are shown in Figure 8.2d. The band shapes were independent of the excitation intensity from 0.1 to 2.0 nJ pulse . The spectrum of the anthracene crystal with vibronic structures is ascribed to the fluorescence originating from the free exdton in the crystalline phase [1, 2], while the broad emission spectra of the pyrene microcrystal centered at 470 nm and that of the perylene microcrystal centered at 605 nm are, respectively, ascribed to the self-trapped exciton in the crystalline phase of pyrene and that of the a-type perylene crystal. These spectra clearly show that the femtosecond NIR pulse can produce excited singlet states in these microcrystals. 

The author has recently carried out some measurements in solution using naphthacene as acceptor.63 As donor, anthracene was chosen rather than pyrene, so as to minimize overlap of the delayed fluorescence of donor and acceptor. A typical delayed emission spectrum from a solution containing 5 X 10 W anthracene and 4 X lO M naphthacene... 

It should not be assumed that all simple mixtures can be analyzed by either of the above techniques. Consider the aromatic hydrocarbon pyrene in the presence of an equal amount of anthracene. The ultraviolet absorption (and fluorescence excitation) spectrum of anthracene completely overlaps that of pyrene. It can be... 

---