Reflection spectrum of the first singlet transition of crystalline anthracene at low temperatures

The b-polarized reflection spectra off the (001) face of anthracene crystals grown from the melt, solution, and by vapor sublimation display fine structure in the region 25 000 to 25 500 cm−1 at temperatures below 70°K. Earlier observations of fine structure by Brodin et al. with sublimation crystals are confirmed and extended. The new results include (i) the temperature dependence of the fine structure between 120° and 2°K, (ii) the reflection spectrum of the higher vibronic transitions, and (iii) studies of the effects of surfaces disrupted by solvent evaporation and photo-oxidation.