Polarized absorption spectrum of phenazine crystal

Abstract

Polarized absorption spectrum of phenazine crystal was measured at 4.2°K. The visible absorption spectrum at about 4300 Å consists of three kinds of differently polarized bands. The band at 22 836 cm −1, which is preferentially polarized along the b crystal axis, was assigned as the 0-0 band of the symmetric allowed n-π ∗ transition ( 1B 3u← 1A g ). The band at 23 090 cm −1 is believed to be a band belonging to a different electronic transition from the allowed n-π ∗ transition on the basis of the polarization behavior and mixed crystal spectra. The two absorption spectra at about 3600 and 2600 Å exhibit large Davydov splittings. They are reasonably assigned as 1B 2u ← 1A g transitions from comparison between calculated and observed Davydov splittings.