Vibrational Assignment of Fluorene from the Infrared and Raman Spectra

The polarized infrared and Raman spectra of a single crystal of fluorene are reported over as wide an energy range as possible. Where this work has overlapped with a recently reported study the agreement has been satisfactory, although, with the data from the c-polarized infrared spectrum and from the low-frequency (50–400 cm−1) region presented here for the first time, several changes in the assignment of the molecular fundamentals are necessary. Some lattice modes of the fluorene crystal were found both in the infrared and Raman spectra and a partial assignment is given.