The polarized reflection and absorption spectra of perylene crystals in monomeric and dimeric forms
Abstract
The electronic absorption spectra of perylene crystals in the α- and β-forms were measured by the normal incidence reflection method in the spectral region from 20 000 to 60 000 cm -1. From the absorption spectrum polarized perpendicular to [1 overline10] axis of the α-form crystal, the bands around 24 000 cm -1 were determined to be polarized along the long molecular axis. Two strong bands with different polarizations were observed around 50 000 cm -1 for each of the α- and β-perylene crystals and were assigned to the transitions to the 1B2 u and 1B3 u states. The observed polarized absorption spectra as a whole were consistent with the theoretical results by Hummel and Ruedenberg and the reflection method was found to be suitable to the polarized absorption measurement of strong bands of crystals. The observed factor-group splittings were compared with the theoretical values, the oriented gas model being found to be applicable to the β-form crystal.
- Publication:
-
Journal of Molecular Spectroscopy
- Pub Date:
- October 1976
- DOI:
- 10.1016/0022-2852(67)90137-3
- Bibcode:
- 1976JMoSp..63...98F