Vibronic spin-orbit interaction in the phosphorescence spectrum of phenazine

Abstract

The polarization of the phosphorescence spectrum (PS) of phenazine in 3-methylpentane and EPA as solvents was measured. If the strong 0, 0 band, which was negative polarized, is disregarded, the other bands are found about equally positive and negative polarized. This indicates the presence of a rather strong inplane component of the emitting oscillator. The Raman and infrared spectra and a sharp PS of phenazine in -heptane as a solvent were recorded. A vibrational analysis of these spectra was performed and the results compared with the polarization of the PS of phenazine in 3-methylpentane and EPA. All negativepolarized lines of the PS could be assigned to Raman frequencies and all positive-polarized lines to infrared modes. The presence of the positive-polarized lines (out-of-plane modes) of appreciable intensity indicated rather strong vibronic spin-orbit (SO) coupling (second-order perturbations) in phenazine. The possible coupling schemes could be:.