Excimers in solid non-crystalline anthracene

By employing time-resolved fluorescence spectroscopy it is shown that the emission spectrum of non-crystalline layers of anthracene, prepared by vacuum sublimation onto a 80 K substrate, consists of three distinct excimer bands. The band maxima are at 21 900 cm-1, 21 500 cm-1 and 19 600 cm-1, the corresponding lifetimes are 10 ns, 35 ns and 170 ns, respectively. The underlying molecular pair conformations, formed during sample preparation, must be metastable in the groundstate.