Knowledge Bank

The polarized Raman spectrum in crystalline anthracene is recorded photographically using $Ar+$ laser as light source. The spectrum is interpreted in the light of theory developed in the previous paper. The results can be summarized as follows: 1. The assignments of $11Ag$ and $9B3g$ normal modes in anthracene, and also 12 $Ag$ and 7 $B3g$ normal modes in anthracene-$d10$ are reported. 2. Among all the normal modes, only one mode shows Davydov's splitting. The lack of exciton structures in Raman spectrum shows clearly that only the totally symmetric component in a vibrational exciton band is Raman active. 3. The intensity distributions among different normal modes and also among different polarizations are related to the intensity distributions in the absorption spectrum of crystalline anthracene.