Reflection Spectra of Acenaphthene Crystals

The reflection spectra have been measured for acenaphthene crystals. The excited states of the acenaphthene molecule are similar to those of the naphthalene molecule; the lower π→π* excited states are observed at 31100 (α), 32600 (p), 43700 (β), and 47400 (β′) cm−1. In the reflection spectra of the crystal, the α and β states polarized along the b axis are observed at 30900 and 41800 cm−1, respectively. The p and β′ states are found at 32100 and 44000 cm−1 in the a axis spectrum and at 31400 and 45000 cm−1 in the c axis spectrum.