First Singlet-Singlet Electronic Transition in the Phenanthrene Molecule and the Band Structure of the Phenanthrene Crystal

Abstract

The absorption and emission spectra of single crystals of phenanthrene have been studied at 20°K. The data show that the transition moment in the molecule is short-axis polarized, and that the factor group splitting in the crystal is 47 cm—1. The emission originates in a region of very weak absorption at a frequency below the main absorption in analogy to several other molecular crystals whose spectra have been studied. It is suggested that the emitting level corresponds to a distorted lattice site.